chore(deps): update dependency prometheus-flask-exporter to v0.20.3 (GoogleCloudPlatform#8226)

Author: renovate-bot

monitoring/opencensus/requirements.txt

@@ -6,5 +6,5 @@ opencensus==0.10.0
 opencensus-context==0.1.2
 opencensus-ext-prometheus==0.2.1
 prometheus-client==0.14.1
-prometheus-flask-exporter==0.20.2
+prometheus-flask-exporter==0.20.3
 requests==2.27.1

monitoring/prometheus/requirements.txt

@@ -3,5 +3,5 @@ google-api-core==2.8.2
 google-auth==2.6.2
 googleapis-common-protos==1.56.4
 prometheus-client==0.14.1
-prometheus-flask-exporter==0.20.2
+prometheus-flask-exporter==0.20.3
 requests==2.27.1