Update golang Docker tag to v1.22 (#131)

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This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| golang |  | minor | `1.21-alpine` -> `1.22-alpine` |
| golang | stage | minor | `1.21` -> `1.22` |

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.woodpecker/test-release.yml

@@ -1,5 +1,5 @@
 variables:
-  - &golang 'golang:1.21-alpine'
+  - &golang 'golang:1.22-alpine'
   - &platforms 'linux/386,linux/amd64,linux/arm/v6,linux/arm/v7,linux/arm64/v8,linux/ppc64le,linux/riscv64,linux/s390x'
   # vars used on push / tag events only
   - publish_logins: &publish_logins

docker/Dockerfile.multiarch

@@ -1,4 +1,4 @@
-FROM --platform=$BUILDPLATFORM golang:1.21 AS build
+FROM --platform=$BUILDPLATFORM golang:1.22 AS build
 ARG TARGETOS TARGETARCH
 
 WORKDIR /src