Update unstable images to Go 1.22rc1

- build/alpine-x64
- build/alpine-x86
- build/release
- combined

refs GH-1304

unstable/build/alpine-x64/Dockerfile

@@ -7,7 +7,7 @@
 
 # https://hub.docker.com/_/golang
 
-FROM golang:1.21.6-alpine3.18
+FROM golang:1.22rc1-alpine3.18
 
 # https://docs.github.com/en/packages/learn-github-packages/connecting-a-repository-to-a-package
 LABEL org.opencontainers.image.source="https://github.com/atc0005/go-ci"

unstable/build/alpine-x86/Dockerfile

@@ -7,7 +7,7 @@
 
 # https://hub.docker.com/_/golang
 
-FROM i386/golang:1.21.6-alpine3.18
+FROM i386/golang:1.22rc1-alpine3.18
 
 # https://docs.github.com/en/packages/learn-github-packages/connecting-a-repository-to-a-package
 LABEL org.opencontainers.image.source="https://github.com/atc0005/go-ci"

unstable/build/release/Dockerfile

@@ -7,7 +7,7 @@
 
 # https://hub.docker.com/_/golang
 
-FROM golang:1.21.6-bookworm
+FROM golang:1.22rc1-bookworm
 
 # https://docs.github.com/en/packages/learn-github-packages/connecting-a-repository-to-a-package
 LABEL org.opencontainers.image.source="https://github.com/atc0005/go-ci"

unstable/combined/Dockerfile

@@ -7,7 +7,7 @@
 
 # https://hub.docker.com/_/golang
 
-FROM golang:1.21.0-bookworm as builder
+FROM golang:1.22rc1-bookworm as builder
 
 # Explicitly disable automatic fetching of Go toolchains newer than the
 # version explicitly provided by this container image.
@@ -62,7 +62,7 @@ RUN echo "Installing golangci-lint@${GOLANGCI_LINT_VERSION}" \
     && golangci-lint --version
 
 
-FROM golang:1.21-bookworm as final
+FROM golang:1.22rc1-bookworm as final
 
 # https://docs.github.com/en/packages/learn-github-packages/connecting-a-repository-to-a-package
 LABEL org.opencontainers.image.source="https://github.com/atc0005/go-ci"