Fix readme update job again (#893)

Author: der-eismann

.github/workflows/release.yaml

@@ -13,7 +13,7 @@ jobs:
       uses: actions/checkout@v3
       with:
         fetch-depth: 0
-        ref: ${{ github.head_ref }}
+        ref: main
     - run: |
         sed -r -i "s/aws-nuke:v[0-9]+\.[0-9]+\.[0-9]+/aws-nuke:${GITHUB_REF#refs/tags/}/" README.md
         sed -r -i "s/aws-nuke-v[0-9]+\.[0-9]+\.[0-9]+/aws-nuke-${GITHUB_REF#refs/tags/}/" README.md