[chore] add riscv64 to k8s release pipeline (#1090)

Author: mowies

.github/workflows/release-k8s.yaml

@@ -11,7 +11,7 @@ jobs:
     with:
       distribution: otelcol-k8s
       goos: '[ "linux" ]'
-      goarch: '[ "amd64", "arm64", "ppc64le", "s390x" ]'
+      goarch: '[ "amd64", "arm64", "ppc64le", "riscv64", "s390x" ]'
       nightly: ${{ contains(github.ref, '-nightly') }}
     secrets: inherit
     permissions: write-all