use go 1.20 build

Author: shynome

.github/workflows/go-ossf-slsa3-publish.yml

@@ -57,7 +57,7 @@ jobs:
     uses: slsa-framework/slsa-github-generator/.github/workflows/builder_go_slsa3.yml@v1.4.0
     needs: args
     with:
-      go-version: 1.19
+      go-version: '1.20'
       config-file: .slsa-goreleaser/${{matrix.os}}-${{matrix.arch}}.yml
       # =============================================================================================================
       #     Optional: For more options, see https://github.com/slsa-framework/slsa-github-generator#golang-projects