Prefer String#tr for other crockford features

[kachick]

ref: #213, #102

⚡ This PR makes 2.5x faster parser.

Before

❯ rake benchmark/parsers.rb
/home/kachick/.rubies/ruby-3.1.2/bin/ruby benchmark/parsers.rb
Warming up --------------------------------------
          ULID.parse     9.091k i/100ms
   ULID.from_integer    39.356k i/100ms
Calculating -------------------------------------
          ULID.parse     91.248k (± 5.4%) i/s -    463.641k in   5.097270s
   ULID.from_integer    391.392k (± 2.7%) i/s -      1.968M in   5.031541s

Comparison:
   ULID.from_integer:   391392.3 i/s
          ULID.parse:    91247.8 i/s - 4.29x  (± 0.00) slower

After

❯ rake benchmark/parsers.rb
/home/kachick/.rubies/ruby-3.1.2/bin/ruby benchmark/parsers.rb
Warming up --------------------------------------
          ULID.parse    20.964k i/100ms
    ULID.decode_time    24.609k i/100ms
   ULID.from_integer    34.517k i/100ms
Calculating -------------------------------------
          ULID.parse    210.466k (± 3.7%) i/s -      1.069M in   5.087177s
    ULID.decode_time    258.681k (± 4.7%) i/s -      1.304M in   5.054055s
   ULID.from_integer    335.660k (± 4.1%) i/s -      1.691M in   5.047816s

Comparison:
   ULID.from_integer:   335660.4 i/s
    ULID.decode_time:   258680.8 i/s - 1.30x  (± 0.00) slower
          ULID.parse:   210466.0 i/s - 1.59x  (± 0.00) slower

❯ rake benchmark_with_other_gems
------------------------------------------------------------------------
#### kachick - ruby-ulid(This one)
cd ./benchmark/compare_with_othergems/kachick
bundle install --quiet
bundle exec ruby -v ./parser.rb
ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-linux]
Warming up --------------------------------------
    ULID.decode_time    16.458k i/100ms
Calculating -------------------------------------
    ULID.decode_time    160.777k (±32.3%) i/s -    740.610k in   5.134636s
"`ruby-ulid gem (this one) - 0.6.0.pre` generated products: 1052719 - sample: [2021-04-27 17:27:22.826 UTC, 2021-04-27 17:27:22.826 UTC, 2021-04-27 17:27:22.826 UTC, 2021-04-27 17:27:22.826 UTC, 2021-04-27 17:27:22.826 UTC]"
cd -
------------------------------------------------------------------------
#### rafaelsales - ulid
cd ./benchmark/compare_with_othergems/rafaelsales
bundle install --quiet
bundle exec ruby -v ./parser.rb
ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-linux]
"`ulid gem - 1.3.0` does not have parsers yet"
cd -
------------------------------------------------------------------------
#### abachman - ulid-ruby
cd ./benchmark/compare_with_othergems/abachman
bundle install --quiet
bundle exec ruby -v ./parser.rb
ruby 3.1.2p20 (2022-04-12 revision 4491bb740a) [x86_64-linux]
Warming up --------------------------------------
           ULID.time     5.826k i/100ms
Calculating -------------------------------------
           ULID.time     60.871k (±13.4%) i/s -    302.952k in   5.077365s
"`ulid-ruby gem - 1.0.2` generated products: 417283 - sample: [2021-04-27 17:27:22.826 UTC, 2021-04-27 17:27:22.826 UTC, 2021-04-27 17:27:22.826 UTC, 2021-04-27 17:27:22.826 UTC, 2021-04-27 17:27:22.826 UTC]"
cd -