Bump to a new oauth2 alpha

Author: jtgeibel

Cargo.lock

@@ -68,7 +68,7 @@ indexmap = "1.0.2"
 jemallocator = { version = "0.3", features = ['unprefixed_malloc_on_supported_platforms', 'profiling'] }
 lettre = { version = "0.10.0-alpha.1", default-features = false, features = ["file-transport", "smtp-transport", "native-tls", "hostname", "builder"] }
 license-exprs = "^1.4"
-oauth2 = { git = "https://github.com/jtgeibel/oauth2-rs", branch = "tokio-1.0", default-features = false, features = ["reqwest-011"] }
+oauth2 = { version = "4.0.0-alpha.3", default-features = false, features = ["reqwest"] }
 parking_lot = "0.11"
 rand = "0.7"
 reqwest = { version = "0.11", features = ["blocking", "gzip", "json"] }