feat: allow specifying a path to flake.nix within the repository

Bumps [cachix/install-nix-action](https://github.com/cachix/install-nix-action) from 16 to 17.
- [Release notes](https://github.com/cachix/install-nix-action/releases)
- [Commits](https://github.com/cachix/install-nix-action/compare/v16...v17)

---
updated-dependencies:
- dependency-name: cachix/install-nix-action
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

.github/dependabot.yml

@@ -0,0 +1,6 @@
+version: 2
+updates:
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+      interval: "daily"

.github/workflows/ci.yml

@@ -12,6 +12,6 @@ jobs:
         with:
           fetch-depth: 0
       - name: Install Nix
-        uses: cachix/install-nix-action@v16
+        uses: cachix/install-nix-action@v17
       - name: Shellcheck
         run: nix-shell --run 'shellcheck $(find . -type f -name "*.sh" -executable)'

.github/workflows/update.yml

@@ -11,7 +11,7 @@ jobs:
       - name: Checkout repository
         uses: actions/checkout@v3
       - name: Install Nix
-        uses: cachix/install-nix-action@v16
+        uses: cachix/install-nix-action@v17
         with:
           extra_nix_config: |
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}

README.md

@@ -122,6 +122,7 @@ jobs:
         uses: DeterminateSystems/update-flake-lock@vX
         with:
           inputs: input1 input2 input3
+          path-to-flake-dir: 'nix/' # in this example our flake doesn't sit at the root of the repository, it sits under 'nix/flake.nix'
 ```
 
 ## Running GitHub Actions CI
@@ -176,6 +177,8 @@ For the bot to produce signed commits, you will have to provide the GPG private
 
 When using commit signing, the commit author name and email for the commits produced by this bot would correspond to the ones associated to the GPG Public Key. 
 
+If you want to sign using a subkey, you must specify the subkey fingerprint using the `gpg-fingerprint` input parameter.
+
 You can find an example of how to using this action with commit signing below:
 
 ```yaml
@@ -198,6 +201,7 @@ jobs:
         with:
           sign-commits: true
           gpg-private-key: ${{ secrets.GPG_PRIVATE_KEY }}
+          gpg-fingerprint: ${{ secrets.GPG_FINGERPRINT }} # specify subkey fingerprint (optional)
           gpg-passphrase: ${{ secrets.GPG_PASSPHRASE }}
 ```
 

action.yml

@@ -17,6 +17,10 @@ inputs:
     description: 'The branch of the PR to be created'
     required: false
     default: "update_flake_lock_action"
+  path-to-flake-dir:
+    description: 'The path of the directory containing `flake.nix` file within your repository. Useful when `flake.nix` cannot reside at the root of your repository.'
+    required: false
+    default: ''
   pr-title:
     description: 'The title of the PR to be created'
     required: false
@@ -57,6 +61,9 @@ inputs:
     description: 'GPG Private Key with which to sign the commits in the PR to be created'
     required: false
     default: ''
+  gpg-fingerprint:
+    description: 'Fingerprint of specific GPG subkey to use'
+    required: false
   gpg-passphrase:
     description: 'GPG Private Key Passphrase for the GPG Private Key with which to sign the commits in the PR to be created'
     required: false
@@ -71,9 +78,10 @@ runs:
     - name: Import bot's GPG key for signing commits
       if: ${{ inputs.sign-commits == 'true' }}
       id: import-gpg
-      uses: crazy-max/ghaction-import-gpg@v4
+      uses: crazy-max/ghaction-import-gpg@v5
       with:
         gpg_private_key: ${{ inputs.gpg-private-key }}
+        fingerprint: ${{ inputs.gpg-fingerprint }}
         passphrase: ${{ inputs.gpg-passphrase }}
         git_config_global: true
         git_user_signingkey: true
@@ -110,6 +118,7 @@ runs:
         GIT_COMMITTER_EMAIL: ${{ env.GIT_COMMITTER_EMAIL }}
         TARGETS: ${{ inputs.inputs }}
         COMMIT_MSG: ${{ inputs.commit-msg }}
+        PATH_TO_FLAKE_DIR: ${{ inputs.path-to-flake-dir }}
     - name: Save PR Body as file
       uses: DamianReeves/write-file-action@v1.1
       with:

flake.lock

@@ -2,11 +2,11 @@
   "nodes": {
     "nixpkgs": {
       "locked": {
-        "lastModified": 1654682581,
-        "narHash": "sha256-Jb1PQCwKgwdNAp907eR5zPzuxV+kRroA3UIxUxCMJ9s=",
+        "lastModified": 1659131907,
+        "narHash": "sha256-8bz4k18M/FuVC+EVcI4aREN2PsEKT7LGmU2orfjnpCg=",
         "owner": "nixos",
         "repo": "nixpkgs",
-        "rev": "e0169d7a9d324afebf5679551407756c77af8930",
+        "rev": "8d435fca5c561da8168abb30270788d2da2a7951",
         "type": "github"
       },
       "original": {

update-flake-lock.sh

@@ -1,6 +1,10 @@
 #!/usr/bin/env bash
 set -euo pipefail
 
+if [[ -n "$PATH_TO_FLAKE_DIR" ]]; then
+  cd "$PATH_TO_FLAKE_DIR"
+fi
+
 if [[ -n "$TARGETS" ]]; then
     inputs=()
     for input in $TARGETS; do