v2.2.0

• Fixed sentence splitting on abbreviations and decimal numbers. A dot no longer ends a sentence between single letters like U.S.A, or between two digits like 3.14, and U.S.A now stays a single token (#14)
• Documented that sentences without words are skipped (#7)
• Replaced Travis with GitHub Actions, running tests on Go 1.8 and the latest release
• Added Codecov reporting, with the build failing below 95 percent coverage
• Raised test coverage to 100 percent, including the previously untested root word replacement
• Fixed a data race in the multi thread test
• Added a code of conduct, contributing guide, security policy, issue templates and a pull request template
• Added a section comparing TextRank to LLMs, and replaced the retired GoDoc badge with pkg.go.dev