v0.17.0

Major Features and Improvements

• feature: migrate to tree-based source APIs
• feature: support merge operation for sources
• feature: support withFallback API for config spec
• fix: fix formatting bug in toml4j's writer when map is in nested list
• fix: filter invalid variables in environment
• refactor: unify info and context in Source API

Breaking Changes

After migrated to tree-based source APIs, many deprecated APIs are removed, including:

• Source: all isXXX and toXXX APIs
• Config: layer, addSource and withSourceFrom