fix: issue:1848 - Docker Image is not building:

* Update public signing key location

Dockerfile

@@ -77,7 +77,7 @@ ENV GLIBC_SHA256 938bceae3b83c53e7fa9cc4135ce45e04aae99256c5e74cf186c794b97473bc
 ENV GLIBCBIN_SHA256 3a87874e57b9d92e223f3e90356aaea994af67fb76b71bb72abfb809e948d0d6
 # Download and install glibc (https://github.com/jeanblanchard/docker-alpine-glibc/blob/master/Dockerfile)
 RUN apk add --update curl && \
-  curl -Lo /etc/apk/keys/sgerrand.rsa.pub https://raw.githubusercontent.com/sgerrand/alpine-pkg-glibc/master/sgerrand.rsa.pub && \
+  curl -Lo /etc/apk/keys/sgerrand.rsa.pub https://github.com/sgerrand/alpine-pkg-glibc/releases/download/$GLIBC_VERSION/sgerrand.rsa.pub && \
   curl -Lo glibc.apk "https://github.com/sgerrand/alpine-pkg-glibc/releases/download/${GLIBC_VERSION}/glibc-${GLIBC_VERSION}.apk" && \
   echo "$GLIBC_SHA256  glibc.apk" | sha256sum -c - && \
   curl -Lo glibc-bin.apk "https://github.com/sgerrand/alpine-pkg-glibc/releases/download/${GLIBC_VERSION}/glibc-bin-${GLIBC_VERSION}.apk" && \