update peter-evans/create-pull-request to v6

Additional changes:

* add clear ABORT message when there are no diffs
* add check of force_run input that runs extract and PR gen even if there are no changes
* add date-time stamp to PR title to make scanning PRs easier in the UI

_NOTE: If extract and PR gen run when there are no changes, a PR will not be created as there are no changes between the action’s branch and the main branch even when force_run is true._

.github/workflows/fetch-licenses.yaml

@@ -20,7 +20,7 @@ jobs:
                   git config --global user.name "GitHub Actions"
                   git config --global user.email "github-actions[bot]@users.noreply.github.com"
     
-            - name: Checkout this repository's auto-update-licenses branch
+            - name: Checkout this repository
               uses: actions/checkout@v4
 
             - name: Checkout official SPDX Repository
@@ -34,11 +34,29 @@ jobs:
                   cp official-spdx-licenses/json/licenses.json cmd/licenses.json
                   cp official-spdx-licenses/json/exceptions.json cmd/exceptions.json
 
+            - name: Get date
+              id: date
+              run: echo "DT_STAMP"=$(date +'%Y-%m-%d %H:%M UTC') >> $GITHUB_ENV
+
             - name: Check for changes
+              id: changes
               run: |
-                  git diff --exit-code -- cmd/licenses.json cmd/exceptions.json || exit 0
+                  has_changes=true
+                  # --quiet: Exits with 1 if there are changes; otherwise, exits with 0
+                  # exiting with anything other than 0 implies the command failed and the command following && will not execute leaving has_changes set to true
+                  # exiting with 0 implies the command was successful and the command following && will be executed setting has_changes to false
+                  git diff --quiet -- cmd/licenses.json cmd/exceptions.json && has_changes=false
+                  if [ $has_changes != 'true' ]; then
+                    if [ ${{ github.event.inputs.force_run }} == 'true' ]; then
+                      echo -e '***************\nNo changes, but skipping abort due to force run\n***************'
+                    else
+                      echo -e '***************\nABORTING: No changes to license data\n***************'
+                    fi
+                  fi
+                  echo "HAS_CHANGES"=$has_changes >> $GITHUB_ENV
                 
             - name: Run license extraction
+              if: ${{ env.HAS_CHANGES == 'true' || github.event.inputs.force_run == 'true' }}
               run: |
                   cd cmd
                   echo "Current branch: $(git branch)"
@@ -47,12 +65,13 @@ jobs:
                   git log --oneline -n 5
 
             - name: Create Pull Request
-              uses: peter-evans/create-pull-request@v3
+              if: ${{ env.HAS_CHANGES == 'true' || github.event.inputs.force_run == 'true' }}
+              uses: peter-evans/create-pull-request@v6
               with:
                   token: ${{ secrets.GITHUB_TOKEN }}
                   commit-message: Add updated license files
                   branch: auto-update-licenses
                   base: main
-                  title: "Update SPDX license files"
-                  body: "The files in this PR are auto-generated by the [fetch-licenses](./.git/workflows/fetch-license.yaml) workflow when it runs the `cmd/extract` script.  It updates SPDX licenses based on the latest released set in the [spdx/license-list-data](https://github.com/spdx/license-list-data) repository maintained by [SPDX](https://spdx.org/licenses/).  \n\nTODO: [spdxexp/spdxlicenses/license_ranges.go](./spdxexp/spdxlicenses/license_range.go) has to be updated manually."
+                  title: "Update SPDX license files (${{ env.DT_STAMP }})"
+                  body: "The files in this PR are auto-generated by the [fetch-licenses](./.git/workflows/fetch-license.yaml) workflow when it runs the `extract` command defined in [cmd/main.go](./cmd/main.go).  It updates SPDX licenses based on the latest released set in the [spdx/license-list-data](https://github.com/spdx/license-list-data) repository maintained by [SPDX](https://spdx.org/licenses/).  \n\nTODO: [spdxexp/spdxlicenses/license_ranges.go](./spdxexp/spdxlicenses/license_range.go) has to be updated manually."
                   labels: 'auto-update,licenses'