v0.3.1: Fix copying env files not in the project root directory (#3)

Fix copying env files not in the project root directory (#3)

Previously env file copying worked only when the following three
directories were the same:

• current directory;
• project root directory;
• the env file's parent directory.

The previous commit wanted to solve this, but it contained a bug. This
also made the automatic tests fail.

This commit fixes that bug.

v0.2.0

Full Changelog: v0.1.2...v0.2.0