Increasing memory limit for installation process.

Increasing memory limit for installation process to avoid this error:

Fatal error: Allowed memory size of 88080384 bytes exhausted (tried to allocate 8208 bytes) in /vendor/doctrine/dbal/lib/Doctrine/DBAL/Types/ArrayType.php on line 58

| Q             | A
| ------------- | ---
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| Refs tickets  | -
| License       | MIT
| Doc PR        | -