chore(deps): update dependency prometheus-client to v0.12.0 (GoogleCloudPlatform#7004)

Co-authored-by: Leah E. Cole <[email protected]>

Author: renovate-bot

monitoring/opencensus/requirements.txt

@@ -5,6 +5,6 @@ googleapis-common-protos==1.53.0
 opencensus==0.8.0
 opencensus-context==0.1.2
 opencensus-ext-prometheus==0.2.1
-prometheus-client==0.11.0
+prometheus-client==0.12.0
 prometheus-flask-exporter==0.18.4
 requests==2.26.0

monitoring/prometheus/requirements.txt

@@ -2,6 +2,6 @@ Flask==2.0.1
 google-api-core==2.2.1
 google-auth==2.0.0
 googleapis-common-protos==1.53.0
-prometheus-client==0.11.0
+prometheus-client==0.12.0
 prometheus-flask-exporter==0.18.4
 requests==2.26.0