Made changes to limit the line length in following files,
- pmb/parse/_apkbuild.py
- pmb/parse/apkindex.py
- pmb/parse/binfmt_info.py
- pmb/parse/deviceinfo.py
- test/test_parse_apkbuild.py
Added the above files in E501 flake8 command list.
Substitute f-string for string concatenation.