Merge [r_base_checkup_ac] into [development]

Installs R with verified gpg key (previously installed without verifying package signature);

Adds tag in DDMMMYY format;

Adds user "acervant" to list of maintainers;

All CVEs have justifications provided in VAT (https://vat.dso.mil/vat/image?imageName=opensource/r/r-base&tag=4.2.1&branch=r_base_checkup_ac);

For related issue ticket see:

#52 (closed)