chore: upgrade dependencies

[hgiasac]

This pull request updates dependencies across the project to newer versions, focusing on OpenTelemetry, Prometheus, gRPC, and related libraries. It also switches the JSON schema generator from github.com/relychan/jsonschema to github.com/invopop/jsonschema and updates Go version requirements in several places. Additionally, semantic conventions used in OpenTelemetry are bumped to a newer version.

Dependency updates:

• Updated OpenTelemetry dependencies (core, exporters, SDK, and related contrib packages) from various 1.43.0/0.18.0/0.19.0 versions to 1.44.0/0.19.0/0.20.0 across go.mod, example/go.mod, and jsonschema/go.mod. [1] [2] [3]
• Upgraded Prometheus and gRPC dependencies, including github.com/prometheus/common, github.com/grpc-ecosystem/grpc-gateway/v2, and google.golang.org/grpc, to their latest patch versions. [1] [2] [3]
• Bumped Go version requirements to 1.26 in jsonschema/build.sh, jsonschema/go.mod, and example/go.mod. [1] [2] [3]
• Updated semantic conventions import from go.opentelemetry.io/otel/semconv/v1.40.0 to v1.41.0 in both middleware.go and provider.go. [1] [2]

JSON schema generation changes:

• Switched JSON schema library from github.com/relychan/jsonschema to github.com/invopop/jsonschema in jsonschema/generate.go and updated the dependency in jsonschema/go.mod. [1] [2]