Bump go and container base image

- bump golang 1.17 -> 1.18
 - bump alpine 3.14 -> 3.15
 - revendor

 We need to use golang instead of golang:alpine because it does not
 contain git anymore. This should be fine as we are not enabling CGO,
 thus not linking against musl instead of libc.

Signed-off-by: leonnicolas <leonloechner@gmx.de>

.github/workflows/release.yaml

@@ -10,7 +10,7 @@ jobs:
     - name: Set up Go
       uses: actions/setup-go@v2
       with:
-        go-version: 1.17.1
+        go-version: 1.18
     - name: Build kgctl Binaries to Be Released
       run: make release
     - name: Publish Release