Release v0.4.0

What's Changed

• Fix deserialization of Series in case of no values. by @JEnoch in #75
• CI: test against MSRV by @msrd0 in #77
• CI: enable code coverage with tarpaulin uploading to gh-pages by @msrd0 in #78
• CI: make tarpaulin ignore test code by @msrd0 in #79
• implement #[influxdb(tag)] and #[influxdb(ignore)] by @blasrodri in #81
• Assertion should consider case-insensitive keywords by @rcastill in #83
• Batch write support by @sunng87 in #87
• Add h1-client-rustls feature by @JEnoch in #88

New Contributors

• @blasrodri made their first contribution in #81
• @rcastill made their first contribution in #83
• @sunng87 made their first contribution in #87

Full Changelog: v0.3.0...v0.4.0