Release 2.2.1

• Add github workflows

Release 2.2.0

• Upgrade Golang to v1.19

Release 2.1.0

• Replace counter by gauge

Release 2.0.0

• Upgrade Golang
• Upgrade dependencies
• Change default port (cf. https://github.com/prometheus/prometheus/wiki/Default-port-allocations)
• Use Alpine linux instead of Debian (864MB vs 427MB)
• Add new metrics
• Rename metrics