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[bot]]

Merging this branch will increase overall coverage

Impacted Packages	Coverage Δ	:robot:
cmd/go-coverage-report	59.82% (+59.82%)	:star2:

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Coverage by file

| Changed File | Coverage Δ | Total | Covered | Missed | :robot: | |--------------|------------|-------|---------|--------|---------| | cmd/go-coverage-report/changed_files.go | 80.00% (**+80.00%**) | 10 (+10) | 8 (+8) | 2 (+2) | :star2: | | cmd/go-coverage-report/coverage.go | 76.47% (**+76.47%**) | 34 (+34) | 26 (+26) | 8 (+8) | :star2: | | 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) | :star2: | | cmd/go-coverage-report/report.go | 75.89% (**+75.89%**) | 112 (+112) | 85 (+85) | 27 (+27) | :star2: | | 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._