deps: Drop Ruby v2.6 / Require Ruby v2.7+ #235

Job	Run time
test (2.7, gemfiles/jekyll_3.9.gemfile)	24s
test (2.7, gemfiles/jekyll_4.0.gemfile)	25s
test (2.7, gemfiles/jekyll_4.1.gemfile)	31s
test (2.7, gemfiles/jekyll_4.2.gemfile)	32s
test (2.7, gemfiles/jekyll_4.3.gemfile)	26s
test (3.0, gemfiles/jekyll_3.9.gemfile)	16s
test (3.0, gemfiles/jekyll_4.0.gemfile)	13s
test (3.0, gemfiles/jekyll_4.1.gemfile)	11s
test (3.0, gemfiles/jekyll_4.2.gemfile)	13s
test (3.0, gemfiles/jekyll_4.3.gemfile)	14s
test (3.1, gemfiles/jekyll_3.9.gemfile)	18s
test (3.1, gemfiles/jekyll_4.0.gemfile)	18s
test (3.1, gemfiles/jekyll_4.1.gemfile)	19s
test (3.1, gemfiles/jekyll_4.2.gemfile)	18s
test (3.1, gemfiles/jekyll_4.3.gemfile)	14s
test (3.2, gemfiles/jekyll_3.9.gemfile)	13s
test (3.2, gemfiles/jekyll_4.0.gemfile)	12s
test (3.2, gemfiles/jekyll_4.1.gemfile)	13s
test (3.2, gemfiles/jekyll_4.2.gemfile)	18s
test (3.2, gemfiles/jekyll_4.3.gemfile)	13s
test (3.3, gemfiles/jekyll_3.9.gemfile)	17s
test (3.3, gemfiles/jekyll_4.0.gemfile)	13s
test (3.3, gemfiles/jekyll_4.1.gemfile)	13s
test (3.3, gemfiles/jekyll_4.2.gemfile)	13s
test (3.3, gemfiles/jekyll_4.3.gemfile)	13s
	7m 10s

Provide feedback