Test/fix broken r checks #13

Job	Run time
R Package Checks / codecov / test-coverage	1m 35s
R Package Checks / check-R-updates / updated-files	6s
R Package Checks / docs-check / docs-check	1m 32s
R Package Checks / lintr / lint	1m 38s
R Package Checks / r-cmd-check / macOS-latest (release)	2m 36s
R Package Checks / r-cmd-check / windows-latest (release)	5m 44s
R Package Checks / r-cmd-check / windows-latest (3.6)	4m 31s
R Package Checks / r-cmd-check / windows-latest (4.1)	4m 53s
R Package Checks / r-cmd-check / ubuntu-latest (release)	1m 47s
R Package Checks / r-cmd-check / ubuntu-latest (devel)	9m 49s
R Package Checks / r-cmd-check / ubuntu-latest (oldrel-1)	3m 53s
R Package Checks / r-cmd-check / ubuntu-latest (oldrel-2)	2m 45s
R Package Checks / r-cmd-check / ubuntu-latest (oldrel-3)	3m 12s
R Package Checks / r-cmd-check / ubuntu-latest (oldrel-4)	3m 8s
R Package Checks / version-check / version-check	1m 20s
	48m 29s

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