unix/linux: update Dockerfile to Go 1.17.3

Change-Id: I14bced7165e0d3307950e922048cd38b1197f5fe
Reviewed-on: https://go-review.googlesource.com/c/sys/+/361994
Trust: Tobias Klauser <tobias.klauser@gmail.com>
Run-TryBot: Tobias Klauser <tobias.klauser@gmail.com>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Matt Layher <mdlayher@gmail.com>
diff --git a/unix/linux/Dockerfile b/unix/linux/Dockerfile
index 6310724..c406ccc 100644
--- a/unix/linux/Dockerfile
+++ b/unix/linux/Dockerfile
@@ -21,9 +21,9 @@
 RUN git clone --branch release/2.34/master --depth 1 https://sourceware.org/git/glibc.git
 
 # Get Go
-ENV GOLANG_VERSION 1.17.1
+ENV GOLANG_VERSION 1.17.3
 ENV GOLANG_DOWNLOAD_URL https://golang.org/dl/go$GOLANG_VERSION.linux-amd64.tar.gz
-ENV GOLANG_DOWNLOAD_SHA256 dab7d9c34361dc21ec237d584590d72500652e7c909bf082758fb63064fca0ef
+ENV GOLANG_DOWNLOAD_SHA256 550f9845451c0c94be679faf116291e7807a8d78b43149f9506c1b15eb89008c
 
 RUN curl -fsSL "$GOLANG_DOWNLOAD_URL" -o golang.tar.gz \
     && echo "$GOLANG_DOWNLOAD_SHA256  golang.tar.gz" | sha256sum -c - \