v2.6.36

IMPROVEMENTS

• add GCS_SA_EMAIL option to support service account authorization, fix 1246 thanks @kamushadenes
• improve --hardlink-exists-files behavior, will look to exists local backups for the same part to avoid download unnecessary, fix 1244
• add S3_CHUNK_SIZE option to allow more flexible workload for S3-compatible remote storage, fix 1248 thanks @KimDoKy