upgrade libpng to fix CVE-2026-22695 and CVE-2026-22801

Author: sunnywu

scripts/azure-cc/Dockerfile

@@ -2,7 +2,7 @@
 FROM eclipse-temurin@sha256:79f8eb45e1219ce03b48d045b1ee920ea529acceb7ff2be6fad7b0b5cb6f07e0
 
 # Install necessary packages and set up virtual environment
-RUN apk update && apk add --no-cache jq python3 py3-pip && \
+RUN apk update && apk add --no-cache --upgrade libpng && apk add --no-cache jq python3 py3-pip && \
     python3 -m venv /venv && \
     . /venv/bin/activate && \
     pip install --no-cache-dir requests azure-identity azure-keyvault-secrets && \

scripts/gcp-oidc/Dockerfile

@@ -5,7 +5,7 @@ LABEL "tee.launch_policy.allow_env_override"="API_TOKEN_SECRET_NAME,DEPLOYMENT_E
 LABEL "tee.launch_policy.log_redirect"="always"
 
 # Install Packages
-RUN apk update && apk add --no-cache jq python3 py3-pip && \
+RUN apk update && apk add --no-cache --upgrade libpng && apk add --no-cache jq python3 py3-pip && \
     python3 -m venv /venv && \
     . /venv/bin/activate && \
     pip install --no-cache-dir google-cloud-secret-manager google-auth google-api-core packaging && \