Merge branch 'rubocop/enable-unneeded-capital-w-cop' into 'master'

Enable Style/UnneededCapitalW Rubocop cop

## What does this MR do?

This MR enables Rubocop cop that checks if `%W[]`, which supports interpolation, is needed.

## What are the relevant issue numbers?

#17478 

See merge request !5010

.rubocop.yml

@@ -681,7 +681,7 @@ Style/UnlessElse:
 # Checks for %W when interpolation is not needed.
 Style/UnneededCapitalW:
-  Enabled: false
+  Enabled: true
 # TODO: Enable UnneededInterpolation Cop.
 # Checks for strings that are just an interpolated expression.

lib/gitlab/key_fingerprint.rb

@@ -39,7 +39,7 @@ module Gitlab
       # OpenSSH 6.8 introduces a new default output format for fingerprints.
       # Check the version and decide which command to use.
-      version_output, version_status = popen(%W(ssh -V))
+      version_output, version_status = popen(%w(ssh -V))
       return false unless version_status.zero?
       version_matches = version_output.match(/OpenSSH_(?<major>\d+)\.(?<minor>\d+)/)

spec/lib/gitlab/popen_spec.rb

@@ -10,7 +10,7 @@ describe 'Gitlab::Popen', lib: true, no_db: true do
   context 'zero status' do
     before do
-      @output, @status = @klass.new.popen(%W(ls), path)
+      @output, @status = @klass.new.popen(%w(ls), path)
     end
     it { expect(@status).to be_zero }
@@ -19,7 +19,7 @@ describe 'Gitlab::Popen', lib: true, no_db: true do
   context 'non-zero status' do
     before do
-      @output, @status = @klass.new.popen(%W(cat NOTHING), path)
+      @output, @status = @klass.new.popen(%w(cat NOTHING), path)
     end
     it { expect(@status).to eq(1) }
@@ -34,7 +34,7 @@ describe 'Gitlab::Popen', lib: true, no_db: true do
   context 'without a directory argument' do
     before do
-      @output, @status = @klass.new.popen(%W(ls))
+      @output, @status = @klass.new.popen(%w(ls))
     end
     it { expect(@status).to be_zero }