axios

Fixes and Functionality:

• Fixing requestHeaders.Authorization (#3287)
• Fixing node types (#3237)
• Fixing axios.delete ignores config.data (#3282)
• Revert "Fixing overwrite Blob/File type as Content-Type in browser. (#1773)" (#3289)
• Fixing an issue that type 'null' and 'undefined' is not assignable to validateStatus when typescript strict option is enabled (#3200)

Internal and Tests:

• Lock travis to not use node v15 (#3361)

Documentation:

• Fixing simple typo, existant -> existent (#3252)
• Fixing typos (#3309)

Huge thanks to everyone who contributed to this release via code (authors listed below) or via reviews and triaging on GitHub: