Use Alpine 3.21 for the docker images (go-gitea#32924)

Author: techknowlogick

Dockerfile

@@ -1,5 +1,5 @@
 # Build stage
-FROM docker.io/library/golang:1.23-alpine3.20 AS build-env
+FROM docker.io/library/golang:1.23-alpine3.21 AS build-env
 
 ARG GOPROXY
 ENV GOPROXY=${GOPROXY:-direct}
@@ -41,7 +41,7 @@ RUN chmod 755 /tmp/local/usr/bin/entrypoint \
               /go/src/code.gitea.io/gitea/environment-to-ini
 RUN chmod 644 /go/src/code.gitea.io/gitea/contrib/autocompletion/bash_autocomplete
 
-FROM docker.io/library/alpine:3.20
+FROM docker.io/library/alpine:3.21
 LABEL maintainer="[email protected]"
 
 EXPOSE 22 3000

Dockerfile.rootless

@@ -1,5 +1,5 @@
 # Build stage
-FROM docker.io/library/golang:1.23-alpine3.20 AS build-env
+FROM docker.io/library/golang:1.23-alpine3.21 AS build-env
 
 ARG GOPROXY
 ENV GOPROXY=${GOPROXY:-direct}
@@ -39,7 +39,7 @@ RUN chmod 755 /tmp/local/usr/local/bin/docker-entrypoint.sh \
               /go/src/code.gitea.io/gitea/environment-to-ini
 RUN chmod 644 /go/src/code.gitea.io/gitea/contrib/autocompletion/bash_autocomplete
 
-FROM docker.io/library/alpine:3.20
+FROM docker.io/library/alpine:3.21
 LABEL maintainer="[email protected]"
 
 EXPOSE 2222 3000