docker run -e EXPORT_PKG=true -e CHECKSUM_SRC=true -e PGPKEY="$PGP_KEY" -v "$(pwd):/pkg" danysk/makepkg:latest

-v "$(pwd):/pkg"             | bind mount a local folder to the container working dir  
-e EXPORT_PKG=true/false     | Used to export build package to the mounted folder  
-e CHECKSUM_SRC=true/false   | Used to verify checksum from the downloaded source and not from the PKGBUILD hash  
-e PGPKEY="$PGP_KEY"         | Used to sign the package with $PGP_KEY, $PGP_KEY should be encoded in base64  
                             | ....PGP_KEY=$(base64 /path/to/key.pgp)  
                             |  
-e CUSTOM_EXEC="{cmds}"      | Used to run custom bash commands before the build  
                             | ....CUSTOM_EXEC="ls ./ && rm -f file"