Run release action against triggering tag instead of checking out branch

Previously, the action would trigger on a tag like `v7.12.3` and would then use
regex to checkout `v7.12.x`, which it would use for generating goreleaser artifacts.

If I'm parsing things correctly, this means that creating a tag and then adding extra
commits on top of 7.12.x _could_ cause us to build the wrong thing.

Instead, this just checks out whatever github ref triggered the action and builds that.

.github/workflows/release.yml

@@ -1,5 +1,5 @@
 # .github/workflows/release.yaml
-name: goreleaser
+name: Generate Release Artifacts
 
 on:
   push:
@@ -18,15 +18,11 @@ jobs:
   goreleaser:
     runs-on: ubuntu-latest
     steps:
-      - name: Set Branch
-        id: set_branch
-        run: |
-          echo "branch=${GITHUB_REF_NAME%.*}.x" >> $GITHUB_OUTPUT
       - name: Checkout
         uses: actions/checkout@v4
         with:
           fetch-depth: 0
-          ref: ${{ steps.set_branch.outputs.branch }}
+          ref: ${{ github.ref_name }}
       - uses: actions/setup-node@v4
         with:
           node-version: 20