Add existing tag check to release workflow

.github/workflows/release.yml

@@ -15,11 +15,25 @@ on:
         default: false
         type: boolean
 jobs:
+  validate-tag:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: mukunku/tag-exists-action@v1.6.0
+        id: check-tag
+        with:
+          tag: ${{ github.event.inputs.version }}
+      - name: Fail if tag exists
+        if: steps.check-tag.outputs.exists == 'true'
+        run: |
+          echo "Tag already exists. Please use a different version."
+          exit 1
+
   tag-and-release:
     runs-on: ubuntu-latest
     if: ${{ github.ref_type == 'branch' }}
     permissions:
       contents: write
+    needs: validate-tag
     steps:
       - name: Log Inputs
         run: |
@@ -86,7 +100,7 @@ jobs:
   build:
     name: Build distribution 📦
     runs-on: ubuntu-latest
-
+    needs: validate-tag
     steps:
       - uses: actions/checkout@v4
         with:

CHANGELOG.md

@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Update most fonts to subset to reduce distribution size.
 
+### Fixed
+
+- Add tag check to release workflow to prevent change with an existing tag.
+
 ### Removed
 
 - Unused python script for generating invoice PDF (`invoice.py`)