Create release notes template

RELEASE_NOTES.template.md

@@ -0,0 +1,7 @@
+## Validator Changes
+
+* no changes
+
+## Other code changes
+
+* no changes

release-branch-pipeline.yml

@@ -12,13 +12,13 @@ variables:
 steps:
   # Checks if the release notes file is populated. Exits if it is not.
   - bash: |
-      if [ -s RELEASE_NOTES.md ]
-      then
-            echo "RELEASE_NOTES.md has data, proceeding to next step."
-      else
-            echo "Your RELEASE_NOTES.md file is empty. Please provide release notes before creating a release."
-            exit 1
-      fi
+      if [ -n "$(cmp RELEASE_NOTES.md RELEASE_NOTES.template.md)" ]
+        then
+          echo "RELEASE_NOTES.md has changed, proceeding to next step"
+        else
+          echo "Your RELEASE_NOTES.md file is unchanged. Please provide release notes before creating a release."
+          exit 1
+    fi
 
   # This task pulls the <version> value from the org.hl7.fhir.r5 project pom.xml file. All modules are released as 
   # the same version, at the same time, as defined in the root level pom.xml.