v2.2.0

BioAlignments v2.2.0

Diff since v2.1.0

Closed issues:

• TagBot not triggering. (#67)
• Do these methods work and are they tested? (#74)

Merged pull requests:

• Add more SubstitutionMatrix operations (#60) (@timholy)
• Add downstream tests (#70) (@CiaranOMara)
• Add ssh key to TagBot workflow (#71) (@CiaranOMara)
• BioSequences v3 and BioSymbols v5 (#72) (@CiaranOMara)
• Housekeeping (#77) (@CiaranOMara)
• Doctests (#78) (@CiaranOMara)