New upstream release - 1.35
    
    - Test for scratch opt in the actual argument of container_build_koji
      (pbabinca)
    - Move the GitIgnore class to its own module (bochecha)
    - Modernize the gitignore-handling code (bochecha)
    - gitignore: Properly handle adding matching lines (bochecha)
    - Refactor: remove unnecessary code (pbabinca)
    - Move custom UnknownTargetError to errors module (pbabinca)
    - New command: container-build (jluza)
    - lookaside: Take over file uploads (bochecha)
    - Remove unnecessary log message (bochecha)
    - Stop making source files read-only (bochecha)
    - Drop some useless comments (bochecha)
    - Only report we're uploading when we actually are (bochecha)
    - lookaside: Check if a file already was uploaded (bochecha)
    - lookaside: Allow client-side and custom CA certificates (bochecha)
    - lookaside: Be more flexible when building the download URL (bochecha)
    - lookaside: Use the hashtype for the URL interpolation (bochecha)
    - lookaside: Add a progress callback (bochecha)
    - lookaside: Handle downloading of source files (bochecha)
    - lookaside: Move handling of file verification (bochecha)
    - lookaside: Move handling of file hashing (bochecha)
    - utils: Add a new warn_deprecated helper (bochecha)
    - Add a new lookaside module (bochecha)
    - Add a new utils module (bochecha)
    - Properly set the logger (bochecha)
    - Move our custom errors to their own module (bochecha)
    - Don't assume MD5 for the lookaside cache (bochecha)
    - Remove dead code (bochecha)
    - Use the proper exception syntax (bochecha)