feat: .gitrelease file for container build

Generate a .gitrelease file as the final step of the @semantic-release
action. This way the file will be available in the followup docker
image build step, but not part of the committed changelog.

templates/.github/workflows/30-release-and-build.yaml.j2

@@ -68,7 +68,7 @@ jobs:
             }
           ]
         additional-packages: |
-          ['@semantic-release/changelog', '@semantic-release/git']
+          ['@semantic-release/changelog', '@semantic-release/git', '@semantic-release/exec']
         repository-url: 'https://github.com/${{ github.repository_owner }}/${{ env.CI_REPOSITORY_NAME }}.git'
         tag-format: 'v${version}'
       env:

templates/.releaserc

@@ -14,6 +14,12 @@
               ],
               "message": "chore(release): ${nextRelease.version} [skip ci]\n\n${nextRelease.notes}"
           }
+      ],
+      [
+        "@semantic-release/exec",
+        {
+          "publishCmd": "echo ${nextRelease.version} > .gitrelease"
+        }
       ]
    ]
 }