standardize the version inside the phpstan directory

Hello,

we have -dev in the directory structure for phostan

phpstan/fusiondirectory/1.4-dev/

this should be normalized with the release major release number 1.4, 1.5 etc..

changed milestone to %FusionDirectory 1.4

assigned to @bmortier

added PJ1802-0188 label

created branch 47-standardize-the-version-inside-the-phpstan-directory to address this issue

mentioned in commit 05adc8ee