Update supported go version to 1.18.* and 1.19.*

Client: go

Also provide generic version of Pointer helper function.
diff --git a/build/docker/ubuntu-bionic/Dockerfile b/build/docker/ubuntu-bionic/Dockerfile
index 4518df7..54b384e 100644
--- a/build/docker/ubuntu-bionic/Dockerfile
+++ b/build/docker/ubuntu-bionic/Dockerfile
@@ -132,9 +132,9 @@
       libglib2.0-dev
 
 # golang
-ENV GOLANG_VERSION 1.18.1
+ENV GOLANG_VERSION 1.19
 ENV GOLANG_DOWNLOAD_URL https://go.dev/dl/go$GOLANG_VERSION.linux-amd64.tar.gz
-ENV GOLANG_DOWNLOAD_SHA256 b3b815f47ababac13810fc6021eb73d65478e0b2db4b09d348eefad9581a2334
+ENV GOLANG_DOWNLOAD_SHA256 464b6b66591f6cf055bc5df90a9750bf5fbc9d038722bb84a9d56a2bea974be6
 RUN curl -fsSL "$GOLANG_DOWNLOAD_URL" -o golang.tar.gz && \
       echo "$GOLANG_DOWNLOAD_SHA256  golang.tar.gz" | sha256sum -c - && \
             tar -C /usr/local -xzf golang.tar.gz && \