docs: extended instructions for "contributing"

[jkowalleck]

supersedes https://github.com/CycloneDX/cyclonedx-python-lib/pull/773/files#r1954324461

[codacy-production]

Coverage summary from Codacy

See diff coverage on Codacy

Coverage variation	Diff coverage
✅ +0.00%	✅ ∅ (target: 80.00%)

Coverage variation details

	Coverable lines	Covered lines	Coverage
Common ancestor commit (82e0bb1)	5101	4769	93.49%
Head commit (57ce9d8)	5101 (+0)	4769 (+0)	93.49% (+0.00%)

Coverage variation is the difference between the coverage for the head and common ancestor commits of the pull request branch: <coverage of head commit> - <coverage of common ancestor commit>

Diff coverage details

	Coverable lines	Covered lines	Diff coverage
Pull request (#783)	0	0	∅ (not applicable)

Diff coverage is the percentage of lines that are covered by tests out of the coverable lines that the pull request added or modified: <covered lines added or modified>/<coverable lines added or modified> * 100%

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_{Codacy stopped sending the deprecated coverage status on June 5th, 2024. Learn more}