Remove resync-build workflow (#1186)

The `resync-build` workflow copies a set of generated files from
`ci-mgmt` into the respective provider repo.


https://github.com/pulumi/ci-mgmt/blob/5c4c4b9781e6baeba99ed540065bcc4c2be763c9/provider-ci/internal/pkg/templates/bridged-provider/.github/workflows/resync-build.yml#L34

These files are no longer available in `ci-mgmt`, which makes this
workflow deprecated. Cleaning up as a result.

provider-ci/internal/pkg/generate.go

@@ -112,12 +112,14 @@ func getDeletedFiles(templateName string) []string {
 	case "bridged-provider":
 		return []string{
 			".github/workflows/check-upstream-upgrade.yml",
+			".github/workflows/resync-build.yml",
 			"scripts/upstream.sh",
 			".goreleaser.yml",
 			".goreleaser.prerelease.yml",
 		}
 	case "external-bridged-provider":
 		return []string{
+			".github/workflows/resync-build.yml",
 			"scripts/upstream.sh",
 			".goreleaser.yml",
 			".goreleaser.prerelease.yml",