Merge pull request #5600 from lucab/to-upstream/armored-sigs

doc: sign release artifacts in armor mode

Documentation/dev-internal/release.md

@@ -66,7 +66,7 @@ The following commands are used for public release sign:
 
 ```
 cd release
-for i in etcd-*{.zip,.tar.gz}; do gpg2 --default-key $SUBKEYID --output ${i}.asc --detach-sign ${i}; done
+for i in etcd-*{.zip,.tar.gz}; do gpg2 --default-key $SUBKEYID --armor --output ${i}.asc --detach-sign ${i}; done
 for i in etcd-*{.zip,.tar.gz}; do gpg2 --verify ${i}.asc ${i}; done
 ```