Remove deprecated set-output (#4)

* Remove deprecated set-output

https://github.blog/changelog/2022-10-11-github-actions-deprecating-save-state-and-set-output-commands/

https://github.com/reverielabs/reverie/pull/7068

* minor style fixes

Author: dmerrick

entrypoint.sh

@@ -2,7 +2,7 @@
 
 # Clean the branch name by replacing / with a .
 function clean {
-    local cleaned=`echo $1 | sed 's,/,.,g'`
+    local cleaned=$(echo $1 | sed 's,/,.,g')
     echo "$cleaned"
 }
 
@@ -20,23 +20,23 @@ if  [[ $var_to_use == refs/tags/* ]]
 then
     # These look something like refs/tags/<tag-name>. Extract <tag-name>.
     result="$(clean ${var_to_use/refs\/tags\//})"
-    echo "::set-output name=tag::$result"
+    echo "tag=$result" >> "$GITHUB_OUTPUT"
 elif  [[ $var_to_use == refs/heads/* ]]
 then
-	# These look something like refs/heads/<branch-name>. Extract <branch-name>.
+    # These look something like refs/heads/<branch-name>. Extract <branch-name>.
     result="$(clean ${var_to_use/refs\/heads\//})"
-    echo "::set-output name=tag::$result"
+    echo "tag=$result" >> "$GITHUB_OUTPUT"
 elif  [[ $var_to_use == refs/pull/* ]]
 then
     # These look something like refs/pull/<pr-number>/merge. Extract <pr-number>
     remove_front="${var_to_use/refs\/pull\//}"
     remove_back="${remove_front%/merge}"
     result="$(clean $remove_back)"
-    echo "::set-output name=tag::pr-$result"
+    echo "tag=pr-$result" >> "$GITHUB_OUTPUT"
 else
-	# If it doesn't match one of those, it's just a vanilla ref. Make sure it's docker-compatible.
-	result="$(clean $var_to_use)"
-    echo "::set-output name=tag::$result"
+    # If it doesn't match one of those, it's just a vanilla ref. Make sure it's docker-compatible.
+    result="$(clean $var_to_use)"
+    echo "tag=$result" >> "$GITHUB_OUTPUT"
 fi