Bump RuboCop Performance to 1.10

[koic]

This PR bumps RuboCop Performance to 1.10 and suppresses the new Performance/RedundantSplitRegexpArgument cop's offenses.

% bundle exec rubocop
(snip)

Offenses:

lib/rubocop/cop/mixin/preferred_delimiters.rb:18:42: C: [Corrected]
Performance/RedundantSplitRegexpArgument: Use string as argument instead
of regexp.
        preferred_delimiters[type].split(//)
                                         ^^
lib/rubocop/cop/mixin/preferred_delimiters.rb:18:42: C: [Corrected]
Style/StringLiterals: Prefer single-quoted strings when you don't need
string interpolation or special symbols.
        preferred_delimiters[type].split("")
                                         ^^
lib/rubocop/cop/style/command_literal.rb:168:58: C: [Corrected]
Performance/RedundantSplitRegexpArgument: Use string as argument instead
of regexp.
          (command_delimiter || default_delimiter).split(//)
                                                         ^^
lib/rubocop/cop/style/command_literal.rb:168:58: C: [Corrected]
Style/StringLiterals: Prefer single-quoted strings when you don't need
string interpolation or special symbols.
          (command_delimiter || default_delimiter).split("")
                                                         ^^
lib/rubocop/cop/style/regexp_literal.rb:153:49: C: [Corrected]
Performance/RedundantSplitRegexpArgument: Use string as argument instead
of regexp.
            ['PreferredDelimiters']['%r'].split(//)
                                                ^^
lib/rubocop/cop/style/regexp_literal.rb:153:49: C: [Corrected]
Style/StringLiterals: Prefer single-quoted strings when you don't need
string interpolation or special symbols.
            ['PreferredDelimiters']['%r'].split("")
                                                ^^
spec/support/alignment_examples.rb:11:26: C: [Corrected]
Performance/RedundantSplitRegexpArgument: Use string as argument instead
of regexp.
  annotated_source.split(/\n\n/).each do |chunk|
                         ^^^^^^

1265 files inspected, 7 offenses detected, 7 offenses corrected

---

Before submitting the PR make sure the following are checked:

• [x ] The PR relates to only one subject with a clear title and description in grammatically correct, complete sentences.
• Wrote good commit messages.
• Commit message starts with [Fix #issue-number] (if the related issue exists).
• Feature branch is up-to-date with master (if not - rebase it).
• Squashed related commits together.
• Added tests.
• Ran bundle exec rake default. It executes all tests and runs RuboCop on its own code.
• Added an entry (file) to the changelog folder named {change_type}_{change_description}.md if the new code introduces user-observable changes. See changelog entry format for details.