[release/v1.20.x] Fix for release workflow (#617)

Clean cherry-pick of #607 to the `release/v1.20.x` branch.

Co-authored-by: Trask Stalnaker <[email protected]>

Author: opentelemetrybot

.github/workflows/reusable-create-collector-contrib-pull-request.yml

@@ -79,11 +79,11 @@ jobs:
           GITHUB_TOKEN: ${{ secrets.BOT_TOKEN }}
           JMX_METRICS_VERSION: ${{ inputs.jmx-metrics-version }}
         run: |
-          message="Update the jmx-metrics version to $VERSION"
+          message="Update the jmx-metrics version to $JMX_METRICS_VERSION"
           # note that @open-telemetry/java-contrib-approvers cannot be used below
           # because opentelemetrybot is not a member of the OpenTelemetry org,
           # and so it cannot @ mention OpenTelemetry org groups
-          body="Update the jmx-metrics version to \`$VERSION\`.
+          body="Update the jmx-metrics version to \`$JMX_METRICS_VERSION\`.
 
           cc @jack-berg @mateuszrzeszutek @rmfitzpatrick @trask
           "