Make the AutoRevision update PR against the tagged branch

We need to update AutoRevision.txt in both the stable and master branches, so
try to do that automatically.

.gitattributes

@@ -20,7 +20,8 @@ COPYING          text
 *.h              text diff=cpp
 *.h.in           text diff=cpp
 *.py             text diff=python
-*.cmd            text eol=crlf
+*.cmd            text
+# eol=crlf
 *.sh             text eol=lf
 *.yaml           text
 *.yml            text

.github/workflows/release.yaml

@@ -13,11 +13,21 @@ jobs:
       - run: git rev-parse --short=5 HEAD > cmake/AutoRevision.txt
       - run: git describe --tags `git rev-list --tags --max-count=1` >> cmake/AutoRevision.txt
       - run: cat cmake/AutoRevision.txt
+      - name: Find target branch
+        id: branch
+        # We're running on a tag so have no direct access to the branch. Find it.
+        # Strip the first 3 components (ref/remotes/username)
+        run: |
+          git diff
+          branch=$(git branch -r --contains HEAD --format '%(refname:strip=3)')
+          echo Target branch is $branch
+          echo branch=$branch >> $GITHUB_OUTPUT
       - name: Create Pull Request
         uses: peter-evans/[email protected]
         with:
+          base: ${{ steps.branch.outputs.branch }}
           commit-message: "Release update of AutoRevision.txt"
-          branch: "release/autorevision"
+          branch: "release/autorevision/{{ steps.branch.outputs.branch }}"
           title: "Release update of AutoRevision.txt"
           body: >
             Automatic changes triggered by a new release.