build(deps): update prometheus-client requirement from 0.16.0 to 0.19.0

[dependabot]

Updates the requirements on prometheus-client to permit the latest version.

Release notes

Sourced from prometheus-client's releases.

v0.19.0

See changelog for details.

Changelog

Sourced from prometheus-client's changelog.

[0.19.0]

This is a large release including multiple breaking changes. Major user-facing improvement of this release is support for the OpenMetrics Protobuf format.

Upgrade guide:

• Don't box before registering.

    registry.register(
        "my_metric",
        "This is my metric",
  -      Box::new(my_metric.clone()),
  +      my_metric.clone(),
    );

• Gauge uses i64 instead of u64.

    my_gauge
  -     .set(42u64);
  +     .set(42i64);

• Derive EncodeLabelSet for struct and EncodeLabelValue for enum instead of just Encode for all and require Debug.

  - #[derive(Clone, Hash, PartialEq, Eq, Encode)]
  + #[derive(Clone, Hash, PartialEq, Eq, EncodeLabelSet, Debug)]
    struct Labels {
        path: String,
        method: Method,
        some_number: u64,
    }
  
  #[derive(Clone, Hash, PartialEq, Eq, Encode)]
  
  
  #[derive(Clone, Hash, PartialEq, Eq, EncodeLabelValue, Debug)]
  enum Method {
  Get,
  #[allow(dead_code)]
  Put,
  }

Encode as utf-8 and not as [u8].

- let mut buffer = vec![];

... (truncated)

Commits

• fc8aa9a chore: Prepare v0.19.0 (#119)
• 68e908c *: Preapre v0.19.0-alpha.2 (#116)
• 1f20c3c src/encoding: Take reference for value (#115)
• b87f6ff src/encoding: Generate EncodeLabelValue for integers (#114)
• c53d47b *: Prepare v0.19.0-alpha (#113)
• 83dd006 encoding/: Adopt serde style encoding (#105)
• 6cd0dba Merge pull request #109 from mxinden/maintainers
• 7c1a620 MAINTAINERS: Add file
• a32d413 Merge pull request #104 from mxinden/release-v0.18-to-master
• d346956 Merge branch 'release-v0.18' into release-v0.18-to-master
• Additional commits viewable in compare view

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