Closes #119 updates to `derive_var_bcvacritxfl` #425

Job	Run time
Documentation	0s
Render README	0s
Validation	0s
Code Style / Get R version	1s
Spelling / Get R version	1s
Check / (4.1)	4m 21s
Check / (4.2)	4m 51s
Check / (4.3)	3m 30s
Code Coverage / Get R version	1s
Links / Validate Links	5s
Lint / Get R version	1s
Check Templates / Get R version	1s
Man Pages / Get R version	1s
Spelling / Spellcheck	3m 20s
Code Style / Code Style	2m 37s
Code Coverage / Test Coverage	3m 21s
Lint / Lint	2m 40s
Check Templates / Verify	3m 5s
Man Pages / Roxygen	2m 45s
Code Coverage / Generate badge for coverage	5s
	30m 46s

Provide feedback