No Brew command works on new Mac (Catalina)

// Running any brew command yielded

Traceback (most recent call last):
	4: from /usr/local/Homebrew/Library/Homebrew/brew.rb:13:in `<main>`
	3: from /usr/local/Homebrew/Library/Homebrew/brew.rb:13:in `require_relative`
	2: from /usr/local/Homebrew/Library/Homebrew/global.rb:10:in `<top (required)>`
	1: from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require`
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/rubygems/core_ext/kernel_require.rb:54:in `require`: cannot load such file -- active_support/core_ext/object/blank (LoadError)

// Typically this would be fixed using by running 

brew update-reset 

// which instead returned 

xcrun: error: invalid active developer path (/Library/Developer/CommandLineTools), missing xcrun at: /Library/Developer/CommandLineTools/usr/bin/xcrun

// which would typically be fixed by running 

xcode-select --install

// which yielded

xcode-select: note: install requested for command line developer tools

// which triggers a dialogue box asking whether you would like to install command line dev tools. In case it returns an error about not being able to find the software on the Update Server, then download Xcode from the App Store

// Prior to Xcode 12, Xcode itself was not required to install the command line tools using xcode-select. 

// Install a component of XCode called Command Line Tools by following: XCode --> Open Developer Tool --> More Developer tools --> Download the Command Line Tools --> Install

// Then run 

brew update-reset