Revert nvmrc to a widely compatible string #441

Job	Run time
analyze	43s
collect-release-info	14s
collect-docsite-release-info	2s
unpublish_docsite	0s
test (3.0, rails_6_1, rspec_lt_3_10)	2m 12s
build-docsite	0s
test (3.0, rails_6_1, rspec_gte_3_10)	2m 8s
test (3.0, rails_7_0, rspec_lt_3_10)	2m 10s
test (3.0, rails_7_0, rspec_gte_3_10)	2m 17s
test (3.0, no_rails, rspec_lt_3_10)	1m 48s
test (3.0, no_rails, rspec_gte_3_10)	1m 36s
test (3.1, rails_6_1, rspec_lt_3_10)	2m 17s
test (3.1, rails_6_1, rspec_gte_3_10)	2m 19s
test (3.1, rails_7_0, rspec_lt_3_10)	2m 16s
test (3.1, rails_7_0, rspec_gte_3_10)	2m 18s
test (3.1, no_rails, rspec_lt_3_10)	1m 49s
test (3.1, no_rails, rspec_gte_3_10)	1m 45s
test (3.2, rails_6_1, rspec_lt_3_10)	2m 13s
test (3.2, rails_6_1, rspec_gte_3_10)	2m 17s
test (3.2, rails_7_0, rspec_lt_3_10)	2m 19s
publish-docsite	0s
test (3.2, rails_7_0, rspec_gte_3_10)	2m 12s
test (3.2, no_rails, rspec_lt_3_10)	1m 40s
test (3.2, no_rails, rspec_gte_3_10)	1m 39s
test (3.3, rails_6_1, rspec_lt_3_10)	2m 32s
test (3.3, rails_6_1, rspec_gte_3_10)	2m 23s
test (3.3, rails_7_0, rspec_lt_3_10)	2m 27s
test (3.3, rails_7_0, rspec_gte_3_10)	2m 21s
test (3.3, no_rails, rspec_lt_3_10)	1m 46s
test (3.3, no_rails, rspec_gte_3_10)	1m 43s
ready-to-merge	1s
	51m 27s

Provide feedback