Enabled trusted publisher for rubygems.org #232

Job	Run time
ruby-versions / Generate Ruby versions	2s
build (2.5 / ubuntu-latest)	22s
build (2.5 / windows-latest)	3m 37s
build (2.6 / ubuntu-latest)	23s
build (2.6 / macos-latest)	36s
build (2.6 / windows-latest)	2m 47s
build (2.7 / ubuntu-latest)	23s
build (2.7 / macos-latest)	29s
build (2.7 / windows-latest)	3m 8s
build (3.0 / ubuntu-latest)	10s
build (3.0 / macos-latest)	15s
build (3.0 / windows-latest)	1m 8s
build (3.1 / ubuntu-latest)	13s
build (3.1 / macos-latest)	16s
build (3.1 / windows-latest)	1m 13s
build (3.2 / ubuntu-latest)	11s
build (3.2 / macos-latest)	15s
build (3.2 / windows-latest)	1m 51s
build (3.3 / ubuntu-latest)	11s
build (3.3 / macos-latest)	15s
build (3.3 / windows-latest)	2m 10s
build (head / ubuntu-latest)	9s
build (head / macos-latest)	16s
build (truffleruby-head / ubuntu-latest)	37s
build (truffleruby-head / macos-latest)	24s
build (mswin / windows-latest)	1m 59s
build (mingw / windows-latest)	59s
	24m 19s

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