Fix a CI failure on rbs

This commit applies ruby/rbs#1374.

Author: k0kubun

gems/bundled_gems

@@ -17,7 +17,7 @@ net-pop         0.1.2   https://github.com/ruby/net-pop
 net-smtp        0.3.3   https://github.com/ruby/net-smtp
 matrix          0.4.2   https://github.com/ruby/matrix
 prime           0.1.2   https://github.com/ruby/prime
-rbs             3.1.0   https://github.com/ruby/rbs
+rbs             3.1.0   https://github.com/ruby/rbs b943e7e60493ba312a7c9f5f5e0069a40da90320
 typeprof        0.21.7  https://github.com/ruby/typeprof aabc019684d8b4a1ed66c2a1ca48da7bbb18dcc0
 debug           1.8.0   https://github.com/ruby/debug
 racc            1.7.1   https://github.com/ruby/racc