This requires updating to Rubocop 0.49.0 which will require some fixes
to rules, in Homebrew/brew and Homebrew/homebrew-core but opening this
for now so I remember.

This reverts commit 3e4547f5, reversing
changes made to 6edf9382.

Homebrew's actually ended up using a fair few gems. While we want to
avoid Bundler at runtime (and this PR still does that, in fact uses
Bundler even less at runtime than it did before) writing our own version
to use at build-time seems redundant.

This passed a symbol to `:except_cops` which caused a 💥.

This avoids an error when RuboCop installed installed yet.

CC @GauthamGoli FYI.

Also refactor audit cops into two "departments"
 - FormulaAudit
 - FormulaAuditStrict

- Check if the JSON is definitely invalid (< 2 characters)
- Output the arguments that were passed to Rubocop

Another look at the current Rubocop rules and how they fit with our
existing and desired future style. Almost all of these changes were
automatic. Split some rules between formulae/brew where brew doesn't
have millions of cases that need fixed.

This allows having a shared style that’s use for Homebrew/brew and taps
which can be overridden by Homebrew/brew.

If rubocop invocation from brew audit exits with nil exitstatus,
brew audit fails with 'undefined method `>' for nil:NilClass'.

Changes to our style configuration:

- Consolidate all rules related to Ruby 1.8 compatibility in one place.
- Codify our de-facto preference for `alias_method` over `alias` (drops
  offense count by 54 after turning this on).
- Drop `Style/SignalException` as `only_raise` has been the new default
  for quite a while (since RuboCop 0.37.0).

Tweak `Style/NumericLiteralPrefix` cop settings as we're using octal
literals a lot (both in formulae and the package manager) for file
permissions and aren't ready just yet to transition them to the more
beginner-friendly `0o` prefix (instead of the more obscure `0` prefix).

This collects all violations for each formula in a single place, instead
of doing `brew style` outputs for all formulae first, and then the other
audit checks.

Closes #112.

Signed-off-by: Andrew Janke <andrew@apjanke.net>

(#85)

Closes Homebrew/homebrew#49084.

Signed-off-by: Dominyk Tiller <dominyktiller@gmail.com>

Stop using Style/TrailingComma as it is no longer recognized and start using
Style/TrailingCommaInArguments and Style/TrailingCommaInLiteral instead.

Closes Homebrew/homebrew#48144.

Signed-off-by: Xu Cheng <xucheng@me.com>

Closes Homebrew/homebrew#43650.

Signed-off-by: Mike McQuaid <mike@mikemcquaid.com>