Filename value is changed after checking for presence in deploy cache

[bookwyrm]

https://github.com/WP2Static/wp2static-addon-s3/blob/b88e63f09823fc559336abbeaf203ff25dbcc537/src/Deployer.php#L88

Later this changed value is inserted into the cache such that a future execution (likely just on windows) will get an incorrect cache miss.