Modify the requirements.txt file and upgrade all Python libraries to the latest version.

upgrade-requirements.sh

#!/bin/bash

pip list --format=columns --outdated | \
  sed -n '3,$p' | \
  while IFS=" " read -r package old_version new_version extra
  do
    for requirements_file in "$@"
    do
      if grep -q ${package} ${requirements_file}; then
        echo "${package}: ${old_version} -> ${new_version}"
      fi
      sed -i "s#${package}==${old_version}#${package}==${new_version}#" $requirements_file
    done
  done

Usage:

$ ./upgrade-requirements.sh requirements-test.txt requirements.txt