[BREAKING CHANGE] drop use of tindercrypt, and use ring directly

taskchampion/Cargo.toml

@@ -19,12 +19,12 @@ anyhow = "1.0"
 thiserror = "1.0"
 ureq = "^2.1.0"
 log = "^0.4.14"
-tindercrypt = { version = "^0.2.2", default-features = false }
 rusqlite = { version = "0.25", features = ["bundled"] }
 strum = "0.21"
 strum_macros = "0.21"
 flate2 = "1"
 byteorder = "1.0"
+ring = "0.16"
 
 [dev-dependencies]
 proptest = "^1.0.0"