Prevent git errors from showing in command output

This would be a very rare case, but one time the git command failed, printing out an obscure "fatal" message to stderr which caused confusion.

lib/git_utils.rb

@@ -0,0 +1,15 @@
+class GitUtils
+  # Generate a description of the git version based on latest tag.
+  # Eg: "v4.4.4-156-g8afcd82-modified"
+  #  - tag name
+  #  - number of commits since tag
+  #  - commit ID
+  #  - "modified" if uncommitted changes
+  #
+  def self.git_version
+    # Capture stderr so that confusing errors aren't shown in comand output
+    stdout, _stderr, _status = Open3.capture3("git describe --tags --dirty=-modified")
+    # Strip trailing linebreak
+    stdout.strip
+  end
+end