This finally resolved my problem. If anyone has some insight as to why this worked, further insight would be greatly appreciated. I probably have some left over path settings on my system from working with Ruby last year.
hansi$ brew install git
hansi$ git --version
git version 2.19.0
hansi$ brew install git
Warning: git 2.25.1 is already installed, it's just not linked
You can use `brew link git` to link this version.
hansi$ brew link git
Linking /usr/local/Cellar/git/2.25.1...
Error: Could not symlink bin/git
Target /usr/local/bin/git
already exists. You may want to remove it:
rm '/usr/local/bin/git'
To force the link and overwrite all conflicting files:
brew link --overwrite git
To list all files that would be deleted:
brew link --overwrite --dry-run git
hansi$ brew link --overwrite git
Linking /usr/local/Cellar/git/2.25.1... 205 symlinks created
hansi$ git --version
git version 2.25.1