Make: Augment tag-next-release to create Go Modules compatible Git tag

Makefile

@@ -162,12 +162,14 @@ tag-next-release: fetch-git
 	@$(ENSURE_VALID_RELEASE_BRANCH_NAME)
 	@$(ENSURE_NO_CHANGELOG_FRAGMENTS)
 	@$(ENSURE_NEXT_VERSION_IN_CHANGELOG)
-	@$(ECHO_STDERR) "All checks have passed. Proceeding with tagging the $(OASIS_CORE_GIT_ORIGIN_REMOTE)/$(RELEASE_BRANCH)'s HEAD with tag '$(RELEASE_TAG)'."
+	@$(ECHO_STDERR) "All checks have passed. Proceeding with tagging the $(OASIS_CORE_GIT_ORIGIN_REMOTE)/$(RELEASE_BRANCH)'s HEAD with tags:\n- $(RELEASE_TAG)\n- $(RELEASE_TAG_GO)"
 	@$(CONFIRM_ACTION)
 	@$(ECHO_STDERR) "If this appears to be stuck, you might need to touch your security key for GPG sign operation."
 	@git tag --sign --message="Version $(NEXT_VERSION)" $(RELEASE_TAG) $(OASIS_CORE_GIT_ORIGIN_REMOTE)/$(RELEASE_BRANCH)
-	@git push $(OASIS_CORE_GIT_ORIGIN_REMOTE) $(RELEASE_TAG)
-	@$(ECHO_STDERR) "$(CYAN)Tag '$(RELEASE_TAG)' has been successfully pushed to $(OASIS_CORE_GIT_ORIGIN_REMOTE) remote.$(OFF)"
+	@$(ECHO_STDERR) "If this appears to be stuck, you might need to touch your security key for GPG sign operation."
+	@git tag --sign --message="Version $(NEXT_VERSION)" $(RELEASE_TAG_GO) $(OASIS_CORE_GIT_ORIGIN_REMOTE)/$(RELEASE_BRANCH)
+	@git push $(OASIS_CORE_GIT_ORIGIN_REMOTE) $(RELEASE_TAG) $(RELEASE_TAG_GO)
+	@$(ECHO_STDERR) "$(CYAN)Tags:\n- $(RELEASE_TAG)\n- $(RELEASE_TAG_GO)\nhave been successfully pushed to $(OASIS_CORE_GIT_ORIGIN_REMOTE) remote.$(OFF)"
 
 # Prepare release.
 release:

common.mk

@@ -114,6 +114,12 @@ endef
 
 # Git tag of the next release.
 RELEASE_TAG := v$(NEXT_VERSION)
+# Go Modules compatible Git tag of the next release.
+RELEASE_TAG_GO = $(eval RELEASE_TAG_GO := $$(shell \
+	python3 -c "ver_parts = '$(NEXT_VERSION)'.split('.'); \
+		ver_parts.append(0) if len(ver_parts) == 2 else ''; \
+		print('go/v0.{}{:0>2}.{}'.format(*ver_parts))" \
+	))$(RELEASE_TAG_GO)
 
 # Helper that ensures $(RELEASE_BRANCH) variable contains a valid release branch name.
 define ENSURE_VALID_RELEASE_BRANCH_NAME =