YAML configuration files

In Fluent Bit v3.2 and later, YAML configuration files support all of the settings and features that classic configuration files support, plus additional features that classic configuration files don't support, like processors.

YAML configuration files support the following top-level sections:

• env: Configures environment variables.

• includes: Specifies additional YAML configuration files to include as part of a parent file.

• service: Configures global properties of the Fluent Bit service.

• pipeline: Configures active inputs, filters, and outputs.

• parsers: Defines custom parsers.

• multiline_parsers: Defines custom multiline parsers.

• plugins: Defines paths for custom plugins.

• upstream_servers: Defines nodes for output plugins.

YAML configuration is used in the smoke tests for containers. An always-correct up-to-date example is here: https://github.com/fluent/fluent-bit/blob/master/packaging/testing/smoke/container/fluent-bit.yaml.