fix: Re-introduce inputs.pr-title

This is to allow users to override the PR title since the commit message as well as title are processed differently which may lead to errors in how they are displayed. For example, the commit message needs quotations to be escaped

README.md

@@ -28,6 +28,11 @@ jobs:
             access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}
       - name: Update flake.lock
         uses: DeterminateSystems/update-flake-lock@vX
+        with:
+          pr-title: "Update flake.lock" # Title of PR to be created
+          pr-labels: |                  # Labels to be set on the PR
+            dependencies
+            automated
 ```
 
 ## Example updating specific input(s)

action.yml

@@ -9,6 +9,18 @@ inputs:
     description: 'GITHUB_TOKEN or a `repo` scoped Personal Access Token (PAT)'
     required: false
     default: ${{ github.token }}
+  commit-msg:
+    description: 'The message provided with the commit'
+    required: false
+    default: "flake.lock: Update"
+  pr-title:
+    description: 'The title of the PR to be created'
+    required: false
+    default: "flake.lock: Update"
+  pr-labels:
+    description: 'A comma or newline separated list of labels to set on the Pull Request to be created'
+    required: false
+    default: ''
 runs:
   using: "composite"
   steps:
@@ -18,9 +30,9 @@ runs:
           for input in ${{ inputs.inputs }}; do
             inputs+=("--update-input" "$input")
           done
-          nix flake lock "${inputs[@]}" --commit-lock-file
+          nix flake lock "${inputs[@]}" --commit-lock-file --commit-lockfile-summary "${{ inputs.commit-msg }}"
         else
-          nix flake update --commit-lock-file
+          nix flake update --commit-lock-file --commit-lockfile-summary "${{ inputs.commit-msg }}"
         fi
       shell: bash
       env:
@@ -41,8 +53,9 @@ runs:
       with:
         branch: update_flake_lock_action
         delete-branch: true
-        title: "flake.lock: Update"
+        title: ${{ inputs.pr-title }}
         token: ${{ inputs.token }}
+        labels: ${{ inputs.pr-labels }}
         body: |
           Automated changes by the [update-flake-lock](https://github.com/DeterminateSystems/update-flake-lock) GitHub Action.