Resolve "Update repo level docs and release 0.3.0"

Closes #8

See merge request subcom/mquery!6

Resolve "Duration struct's fields are private"

Closes #7

See merge request subcom/mquery!5

Resolve "feat: Transform raw labels to custom data types"

Closes #3

See merge request subcom/mquery!3

Resolve "refactor: Replace QueryResult and Error type with internal types"

Closes #6

See merge request subcom/mquery!4

This removes the need for the user to import types from the `prometheus-http-query` crate where type annotations are required.
These changes also ensure that the public API of mquery remains more stable, as it is decoupled from the external types.

chore: add changelog and release 0.2.0"

Closes #4

See merge request subcom/mquery!2

Closes #2

Feat: Binary Operators with Vector Matching

See merge request subcom/mquery!1