Prepare for v1 release

[fgrosse]

• Update README.md and CHANGELOG.md to point to v1
• Rename $COVERAGE_REPORT_TRIM to $TRIM_PACKAGE
• Rename "-root-pkg" flag to "-root"
• Fail "Download go-coverage-report" job on non-zero status codes
• Move downloading of binary into its own script

[github-actions]

Merging this branch will increase overall coverage

Impacted Packages	Coverage Δ	🤖
cmd/go-coverage-report	59.82% (+59.82%)	🌟

---

Coverage by file

Changed File	Coverage Δ	Total	Covered	Missed	🤖
cmd/go-coverage-report/changed_files.go	80.00% (+80.00%)	10 (+10)	8 (+8)	2 (+2)	🌟
cmd/go-coverage-report/coverage.go	76.47% (+76.47%)	34 (+34)	26 (+26)	8 (+8)	🌟
cmd/go-coverage-report/coverage_test.go	0.00% (ø)	0	0	0
cmd/go-coverage-report/main.go	0.00% (ø)	39 (+39)	0	39 (+39)
cmd/go-coverage-report/profile.go	58.16% (+58.16%)	141 (+141)	82 (+82)	59 (+59)	🌟
cmd/go-coverage-report/report.go	75.89% (+75.89%)	112 (+112)	85 (+85)	27 (+27)	🌟
cmd/go-coverage-report/report_test.go	0.00% (ø)	0	0	0

Please note that the "Total", "Covered", and "Missed" counts above refer to code statements instead of lines of code. The value in brackets refers to the test coverage of that file in the old version of the code.