Workspace: blackfire gpg.key url fixed (laradock#2133)

Author: shov

workspace/Dockerfile

@@ -345,7 +345,7 @@ ARG BLACKFIRE_CLIENT_TOKEN
 ENV BLACKFIRE_CLIENT_TOKEN ${BLACKFIRE_CLIENT_TOKEN}
 
 RUN if [ ${INSTALL_XDEBUG} = false -a ${INSTALL_BLACKFIRE} = true ]; then \
-    curl -L https://packagecloud.io/gpg.key | apt-key add - && \
+    curl -L https://packages.blackfire.io/gpg.key | apt-key add - && \
     echo "deb http://packages.blackfire.io/debian any main" | tee /etc/apt/sources.list.d/blackfire.list && \
     apt-get update -yqq && \
     apt-get install blackfire-agent \