Fix release note generation script (#2056)

Summary: Fix release note generation script

Our releases have blank release notes. This makes it difficult for end
users to understand what has changed between releases. This PR updates
the existing script that was built to auto generate changelog notes.

Relevant Issues: N/A

Type of change: /kind bug

Test Plan: Ran the script for each artifact type and verified the output
was expected
- [x] cli release notes are expected
```
$ ./scripts/create_release_tag.sh cli -n
$ git tag -l --format='%(contents)' release/cli/v0.9.0-pre-ddelnano-fix-release-note-generation.4
### New Features
- (#2048) Enhanced the `px` cli to detect OpenShift clusters
and prompt to install the appropriate SecurityContextConstraints before
proceeding with a deploy
```
- [x] vizier release notes are expected
```
# Needed to modify prev_tag in script since v0.14.13 to main's HEAD doesn't have vizier changelog messages
$ ./scripts/create_release_tag.sh vizier -n
$ git tag -l --format='%(contents)' release/vizier/v0.15.0-pre-main.4
### Bug Fixes
- (#2047) Ensures that the `--stirling_bpf_loop_limit` and
`--stirling_bpf_chunk_limit` values are respected if explicitly provided
on the command line. For 5.1 and later kernels, cli provided values
would have been ignored

```
- [x] cloud release notes are generated correctly
```
$ ./scripts/create_release_tag.sh cloud -n
Generating changelog from release/cloud/v0.1.8..release/cloud/v0.2.0-pre-ddelnano-fix-release-note-generation.1

$ git tag -l --format='%(contents)' release/cloud/v0.2.0-pre-ddelnano-fix-release-note-generation.1
### New Features
- (#2043) Add support for rendering differential flamegraphs in
the `StackTraceFlameGraph` display spec
### Bug Fixes
- (#2041) Upgraded bcc and libbpf to support kernels 6.10 and
later
```

scripts/create_release_tag.sh

@@ -140,34 +140,51 @@ function generate_changelog {
 
         log=$(git log --format=%B -n 1 "$commit")
 
+        # PR title line will be suffixed with (#<PR number>)
+        prTitle=$(echo $log | head -n1)
+        if [[ $prTitle =~ \(\#([0-9]+)\) ]]; then
+          prNum=${BASH_REMATCH[1]}
+        fi
+
         # Get the type of change (cleanup|bug|feature).
         typeRe='Type of change: /kind ([A-Za-z]+)'
         if [[ $log =~ $typeRe ]]; then
           changeType=${BASH_REMATCH[1]}
         fi
 
         # Get release notes.
-        notesRe="\`\`\`release-note\s*(.*)\`\`\`"
-        if [[ $log =~ $notesRe ]]; then
-          releaseNote=${BASH_REMATCH[1]}
-        fi
+        releaseNote=$(echo "$log" |  awk '
+        BEGIN { output = ""; capturing = 0 }
+        /Changelog Message:/ { capturing = 1 }
+        /---------/ { capturing = 0 }
+        /Signed-off-by/ { capturing = 0 }
+        capturing {
+          print $0
+        }
+        ' | sed 's/Changelog Message: //')
 
         declare -a cleanup_changelog
         declare -a bug_changelog
         declare -a feature_changelog
 
         if [[ -n $releaseNote ]]; then
+          fullReleaseNote="(#$prNum) $releaseNote"
           case $changeType in
           "cleanup")
-            cleanup_changelog+=("$releaseNote")
+            cleanup_changelog+=("$fullReleaseNote")
             ;;
           "bug")
-            bug_changelog+=("$releaseNote")
+            bug_changelog+=("$fullReleaseNote")
+            ;;
+          "bugfix")
+            bug_changelog+=("$fullReleaseNote")
             ;;
           "feature")
-            feature_changelog+=("$releaseNote")
+            feature_changelog+=("$fullReleaseNote")
             ;;
           *)
+            # If the type change is wrong, fail so that invalid entries can be fixed
+            exit 1
             ;;
           esac
         fi
@@ -248,6 +265,7 @@ if [ "$RELEASE" != "true" ]; then
   new_version_str=$(update_pre "$new_version_str" "$commit_count" "$sanitized_branch")
 fi
 
+echo "Generating changelog from ${prev_tag}..release/${ARTIFACT_TYPE}/v${new_version_str}"
 changelog=$(generate_changelog "$prev_tag" "$BAZEL_TARGET")
 
 new_tag="release/$ARTIFACT_TYPE/v"$new_version_str