Update Grafana GPG kye

Dockerfile

 FROM debian:stable-slim
 
-COPY grafana.gpg /etc/apt/trusted.gpg.d/
+COPY grafana.gpg /usr/share/keyrings/grafana.gpg
 COPY build.sh /tmp/build.sh
 
 RUN /tmp/build.sh && rm /tmp/build.sh

build.sh

@@ -30,7 +30,7 @@ apt-get update
 install_packages ${BUILD_PACKAGES}
 
 # Install the Grafana repository.
-echo "deb https://packages.grafana.com/oss/deb stable main" \
+echo "deb [signed-by=/usr/share/keyrings/grafana.gpg] https://packages.grafana.com/oss/deb stable main" \
     > /etc/apt/sources.list.d/grafana.list
 apt-get -q update