Add Scala 2.13.16 support #256

Job	Run time
Integration tests	1m 51s
Compiler and SBT plugin tests (ubuntu-latest, 2.12.13)	2m 55s
Build docs	1m 38s
Compiler and SBT plugin tests (ubuntu-latest, 2.12.14)	2m 56s
Check formatting	1m 27s
Compiler and SBT plugin tests (ubuntu-latest, 2.12.15)	3m 0s
Compiler and SBT plugin tests (ubuntu-latest, 2.12.16)	2m 58s
Compiler and SBT plugin tests (ubuntu-latest, 2.12.17)	3m 8s
Compiler and SBT plugin tests (ubuntu-latest, 2.12.18)	2m 58s
Compiler and SBT plugin tests (ubuntu-latest, 2.12.19)	2m 58s
Compiler and SBT plugin tests (ubuntu-latest, 2.12.20)	2m 52s
Compiler and SBT plugin tests (ubuntu-latest, 2.13.5)	3m 3s
Compiler and SBT plugin tests (ubuntu-latest, 2.13.6)	3m 2s
Compiler and SBT plugin tests (ubuntu-latest, 2.13.7)	2m 53s
Compiler and SBT plugin tests (ubuntu-latest, 2.13.8)	3m 11s
Compiler and SBT plugin tests (ubuntu-latest, 2.13.9)	3m 2s
Compiler and SBT plugin tests (ubuntu-latest, 2.13.10)	2m 58s
Compiler and SBT plugin tests (ubuntu-latest, 2.13.11)	2m 56s
Compiler and SBT plugin tests (ubuntu-latest, 2.13.12)	3m 3s
Compiler and SBT plugin tests (ubuntu-latest, 2.13.13)	2m 58s
Compiler and SBT plugin tests (ubuntu-latest, 2.13.14)	3m 6s
Compiler and SBT plugin tests (ubuntu-latest, 2.13.15)	2m 55s
Compiler and SBT plugin tests (ubuntu-latest, 2.13.16)	2m 57s
	1h 4m 45s

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