Add hashsum for release archives

Signed-off-by: Mattias Appelgren <mattias@ppelgren.se>

.travis.yml

@@ -110,7 +110,9 @@ deploy:
   api_key:
     secure: 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
   file_glob: true
-  file: releases/*.tar.gz
+  file:
+    - releases/*.tar.gz
+    - releases/*.tar.gz.sha256sum
   skip_cleanup: true
   on:
     repo: containerd/containerd

Makefile

@@ -226,6 +226,7 @@ release: $(BINARIES)
 	@install -d releases/$(RELEASE)/bin
 	@install $(BINARIES) releases/$(RELEASE)/bin
 	@cd releases/$(RELEASE) && tar -czf ../$(RELEASE).tar.gz *
+	@cd releases && sha256sum $(RELEASE).tar.gz >$(RELEASE).tar.gz.sha256sum
 
 clean: ## clean up binaries
 	@echo "$(WHALE) $@"