Merge branch 'zj-git-2.21-tests' into 'master'

Test using Git 2.21

See merge request gitlab-org/gitlab-ce!27418

.gitlab-ci.yml

-image: "dev.gitlab.org:5005/gitlab/gitlab-build-images:ruby-2.5.3-golang-1.11-git-2.18-chrome-71.0-node-10.x-yarn-1.12-postgresql-9.6-graphicsmagick-1.3.29"
+image: "dev.gitlab.org:5005/gitlab/gitlab-build-images:ruby-2.5.3-golang-1.11-git-2.21-chrome-71.0-node-10.x-yarn-1.12-postgresql-9.6-graphicsmagick-1.3.29"
 
 variables:
   MYSQL_ALLOW_EMPTY_PASSWORD: "1"

.gitlab/ci/frontend.gitlab-ci.yml

@@ -16,7 +16,7 @@
 gitlab:assets:compile:
   <<: *assets-compile-cache
   extends: .dedicated-no-docs-pull-cache-job
-  image: dev.gitlab.org:5005/gitlab/gitlab-build-images:ruby-2.5.3-git-2.18-chrome-71.0-node-8.x-yarn-1.12-graphicsmagick-1.3.29-docker-18.06.1
+  image: dev.gitlab.org:5005/gitlab/gitlab-build-images:ruby-2.5.3-git-2.21-chrome-71.0-node-8.x-yarn-1.12-graphicsmagick-1.3.29-docker-18.06.1
   dependencies:
     - setup-test-env
   services:

.gitlab/ci/rails.gitlab-ci.yml

@@ -86,7 +86,7 @@
 .rspec-metadata-pg-10: &rspec-metadata-pg-10
   <<: *rspec-metadata
   <<: *use-pg-10
-  image: "dev.gitlab.org:5005/gitlab/gitlab-build-images:ruby-2.5.3-golang-1.11-git-2.18-chrome-71.0-node-10.x-yarn-1.12-postgresql-10-graphicsmagick-1.3.29"
+  image: "dev.gitlab.org:5005/gitlab/gitlab-build-images:ruby-2.5.3-golang-1.11-git-2.21-chrome-71.0-node-10.x-yarn-1.12-postgresql-10-graphicsmagick-1.3.29"
 
 .rspec-metadata-mysql: &rspec-metadata-mysql
   <<: *rspec-metadata

changelogs/unreleased/zj-git-2-21-tests.yml

+---
+title: Test using Git 2.21
+merge_request: 27418
+author:
+type: added

doc/install/installation.md

@@ -95,7 +95,7 @@ Make sure you have the right version of Git installed:
 # Install Git
 sudo apt-get install -y git-core
 
-# Make sure Git is version 2.18.0 or higher
+# Make sure Git is version 2.21.0 or higher
 git --version
 ```
 
@@ -110,9 +110,9 @@ sudo apt-get install -y libcurl4-openssl-dev libexpat1-dev gettext libz-dev libs
 
 # Download and compile from source
 cd /tmp
-curl --remote-name --location --progress https://www.kernel.org/pub/software/scm/git/git-2.18.0.tar.gz
-echo '94faf2c0b02a7920b0b46f4961d8e9cad08e81418614102898a55f980fa3e7e4  git-2.18.0.tar.gz' | shasum -a256 -c - && tar -xzf git-2.18.0.tar.gz
-cd git-2.18.0/
+curl --remote-name --location --progress https://www.kernel.org/pub/software/scm/git/git-2.21.0.tar.gz
+echo '85eca51c7404da75e353eba587f87fea9481ba41e162206a6f70ad8118147bee'  git-2.21.0.tar.gz' | shasum -a256 -c - && tar -xzf git-2.21.0.tar.gz
+cd git-2.21.0/
 ./configure
 make prefix=/usr/local all
 

lib/system_check/app/git_version_check.rb

@@ -7,7 +7,7 @@ module SystemCheck
       set_check_pass -> { "yes (#{self.current_version})" }
 
       def self.required_version
-        @required_version ||= Gitlab::VersionInfo.parse('2.18.0')
+        @required_version ||= Gitlab::VersionInfo.parse('2.21.0')
       end
 
       def self.current_version