Error: /Stage[main]/Main/Node[default]/Package[openssl]/ensure: change from absent to present failed: Execution of 'brew install openssl --appdir=/Applications --force' returned 1: Error: Operation already in progress for pkg-config
Another active Homebrew process is already using pkg-config.
Please wait for it to finish or terminate it to continue.
Here is the solution.
rm $(brew --cache)/Formula/*