chore(deps): update alpine docker tag to v3.21.0

Author: renovate[bot]

.github/workflows/release.yml

@@ -122,7 +122,7 @@ jobs:
     runs-on: ubuntu-latest
     needs: goreleaser
     container:
-      image: alpine:3.20.3
+      image: alpine:3.21.0
 
     steps:
       - name: Get latest apks

Dockerfile

@@ -3,5 +3,5 @@ WORKDIR /otc-auth
 COPY . .
 RUN CGO_ENABLED=0 go build .
 
-FROM alpine:3.20.3
+FROM alpine:3.21.0
 COPY --from=builder /otc-auth/otc-auth /usr/local/bin/otc-auth