Bundle is locked to mimemagic (0.3.4) in integration tests

[nard-tech]

Maybe related to #859

mimemagic used in integration test (v0.3.4) is outdated.

As rails/rails#41750 shows, the license of mimemagic was changed to GPL 2.0 and reverted to MIT, and v0.3.4 was yanked.

The latest version of Rails (5.2.5, 6.0.3.6 and 6.1.3.1) do not depends on mimemagic, so we should use these latest Rails.

As I reported on #859, I tried to fix broken CI in #858. At the same time I tried to fix this issue (cf. 4052f18, 77088e0), but I could not fix entire problems due to other complicated reasons.

Links

• https://github.com/ctran/annotate_models/runs/2226347966#step:5:9
• Dependency on mimemagic 0.3.x no longer valid rails/rails#41750
• Replace MimeMagic rails/rails#41751
• New mimemagic version licensed under MIT rails/rails#41757
• Yanked 0.3.x breaks Rails install mimemagicrb/mimemagic#98

Version

• annotate version: 3.1.1
• rails version: 5.2.4.1, 6.0.2.1
• ruby version: 2.4, 2.5, 2.6