feat: add typehint on adapter #350

Job	Run time
Adapter (8.2, async-aws/simple-s3:^1.0, spec/Gaufrette/Adapter/AsyncAwsS3Spec.php)	24s
Adapter (8.2, aws/aws-sdk-php:^3.158, spec/Gaufrette/Adapter/AwsS3Spec.php)	30s
Adapter (8.2, google/apiclient:^2.12, spec/Gaufrette/Adapter/GoogleCloudStorageSpec.php)	21s
Build (8.0)	21s
Adapter (8.2, doctrine/dbal:^2.3, spec/Gaufrette/Adapter/DoctrineDbalSpec.php)	21s
Build (8.1)	24s
Adapter (8.2, doctrine/dbal:^3.4, spec/Gaufrette/Adapter/DoctrineDbalSpec.php)	16s
Build (8.2)	25s
Adapter (8.2, league/flysystem:^1.0, spec/Gaufrette/Adapter/FlysystemSpec.php)	17s
Adapter (8.2, microsoft/azure-storage-blob:^1.0, spec/Gaufrette/Adapter/AzureBlobStore)	17s
Adapter (8.2, mongodb/mongodb:^1.1, spec/Gaufrette/Adapter/GridFSSpec.php)	21s
Adapter (8.2, phpseclib/phpseclib:^2.0, spec/Gaufrette/Adapter/PhpseclibSftpSpec.php)	57s
	4m 54s

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