Bump diesel to 2.0

[leovalais]

Rocket has not released Diesel 2.0 support on crates.io yet.
I also bumped rocket_cors' rev (no breaking change).

Closes #2862

[codecov]

Codecov Report

Merging #2873 (fd0b19a) into dev (f69af4d) will increase coverage by 0.01%.
The diff coverage is 76.92%.

@@             Coverage Diff              @@
##                dev    #2873      +/-   ##
============================================
+ Coverage     37.86%   37.87%   +0.01%     
  Complexity     1693     1693              
============================================
  Files           584      584              
  Lines         17899    17899              
  Branches       2471     2471              
============================================
+ Hits           6777     6779       +2     
+ Misses        10725    10723       -2     
  Partials        397      397              

Flag	Coverage Δ
editoast	72.42% <76.92%> (+0.09%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
editoast/src/generated_data/error/mod.rs	70.58% <ø> (ø)
editoast/src/schema/buffer_stop.rs	78.57% <ø> (ø)
editoast/src/schema/detector.rs	78.57% <ø> (ø)
editoast/src/schema/operation/create.rs	97.43% <ø> (ø)
editoast/src/schema/operation/mod.rs	33.33% <ø> (ø)
editoast/src/schema/operation/update.rs	62.06% <ø> (ø)
editoast/src/schema/signal.rs	78.57% <ø> (ø)
editoast/src/views/infra/edition.rs	96.29% <ø> (ø)
editoast/src/views/infra/errors.rs	75.51% <ø> (ø)
editoast/src/views/infra/mod.rs	98.18% <ø> (ø)
... and 20 more

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[flomonster]

Thanks for this PR. I think we should really consider stop using rocket.