Update CI image to use Go v1.16

Go 1.16 has significant memory improvements as described in
https://gitlab.com/gitlab-org/gitaly/-/issues/3567.

.gitlab/ci/global.gitlab-ci.yml

@@ -159,7 +159,7 @@
     - *assets-cache-push
 
 .use-pg11:
-  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-11-graphicsmagick-1.3.36"
+  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.16-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-11-graphicsmagick-1.3.36"
   services:
     - name: postgres:11.6
       command: ["postgres", "-c", "fsync=off", "-c", "synchronous_commit=off", "-c", "full_page_writes=off"]
@@ -168,7 +168,7 @@
     POSTGRES_HOST_AUTH_METHOD: trust
 
 .use-pg12:
-  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-12-graphicsmagick-1.3.36"
+  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.16-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-12-graphicsmagick-1.3.36"
   services:
     - name: postgres:12
       command: ["postgres", "-c", "fsync=off", "-c", "synchronous_commit=off", "-c", "full_page_writes=off"]
@@ -177,7 +177,7 @@
     POSTGRES_HOST_AUTH_METHOD: trust
 
 .use-pg11-ee:
-  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-11-graphicsmagick-1.3.36"
+  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.16-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-11-graphicsmagick-1.3.36"
   services:
     - name: postgres:11.6
       command: ["postgres", "-c", "fsync=off", "-c", "synchronous_commit=off", "-c", "full_page_writes=off"]
@@ -188,7 +188,7 @@
     POSTGRES_HOST_AUTH_METHOD: trust
 
 .use-pg12-ee:
-  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.14-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-12-graphicsmagick-1.3.36"
+  image: "registry.gitlab.com/gitlab-org/gitlab-build-images:ruby-2.7.2.patched-golang-1.16-git-2.31-lfs-2.9-chrome-89-node-14.15-yarn-1.22-postgresql-12-graphicsmagick-1.3.36"
   services:
     - name: postgres:12
       command: ["postgres", "-c", "fsync=off", "-c", "synchronous_commit=off", "-c", "full_page_writes=off"]