Issue #3321282 by omkar.podey, Wim Leers, tedbow: Add 'declare(strict_types = 1)' where needed

package_manager/src/PathExcluder/GitExcluder.php

package_manager/src/PathExcluder/NodeModulesExcluder.php

package_manager/src/PathExcluder/PathExclusionsTrait.php

...ge_manager/src/PathExcluder/SiteConfigurationExcluder.php

package_manager/src/PathExcluder/SiteFilesExcluder.php

package_manager/src/PathExcluder/SqliteDatabaseExcluder.php

package_manager/src/PathExcluder/TestSiteExcluder.php

package_manager/src/PathExcluder/VendorHardeningExcluder.php

package_manager/src/PathLocator.php

package_manager/src/ProcessFactory.php

package_manager/src/ProjectInfo.php

package_manager/src/Stage.php

package_manager/src/StatusCheckTrait.php

package_manager/src/ValidationResult.php

...age_manager/src/Validator/ComposerExecutableValidator.php

package_manager/src/Validator/ComposerPatchesValidator.php

package_manager/src/Validator/ComposerSettingsValidator.php

package_manager/src/Validator/DiskSpaceValidator.php

package_manager/src/Validator/DuplicateInfoFileValidator.php

...age_manager/src/Validator/EnvironmentSupportValidator.php