Remove pretty_assertions dependency

It was only used in two places. Rather than adding `use
pretty_assertions::*` everywhere, it's easier to remove, and it
removes two additional dependency crates.

Cargo.lock

@@ -1097,7 +1097,6 @@ dependencies = [
  "once_cell",
  "percent-encoding",
  "pgp",
- "pretty_assertions",
  "pretty_env_logger",
  "proptest",
  "quick-xml",
@@ -1184,12 +1183,6 @@ dependencies = [
  "opaque-debug",
 ]
 
-[[package]]
-name = "diff"
-version = "0.1.12"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "0e25ea47919b1560c4e3b7fe0aaab9becf5b84a10325ddf7db0f0ba5e1026499"
-
 [[package]]
 name = "digest"
 version = "0.9.0"
@@ -2500,15 +2493,6 @@ dependencies = [
  "syn",
 ]
 
-[[package]]
-name = "output_vt100"
-version = "0.1.2"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "53cdc5b785b7a58c5aad8216b3dfa114df64b0b06ae6e1501cef91df2fbdf8f9"
-dependencies = [
- "winapi",
-]
-
 [[package]]
 name = "packed_simd"
 version = "0.3.3"
@@ -2724,18 +2708,6 @@ version = "0.2.10"
 source = "registry+https://github.com/rust-lang/crates.io-index"
 checksum = "ac74c624d6b2d21f425f752262f42188365d7b8ff1aff74c82e45136510a4857"
 
-[[package]]
-name = "pretty_assertions"
-version = "1.0.0"
-source = "registry+https://github.com/rust-lang/crates.io-index"
-checksum = "ec0cfe1b2403f172ba0f234e500906ee0a3e493fb81092dac23ebefe129301cc"
-dependencies = [
- "ansi_term",
- "ctor",
- "diff",
- "output_vt100",
-]
-
 [[package]]
 name = "pretty_env_logger"
 version = "0.4.0"

Cargo.toml

@@ -81,7 +81,6 @@ async-std = { version = "1", features = ["unstable", "attributes"] }
 criterion = "0.3"
 futures-lite = "1.12"
 log = "0.4"
-pretty_assertions = "1.0"
 pretty_env_logger = "0.4"
 proptest = { version = "1", default-features = false, features = ["std"] }
 tempfile = "3"

src/mimefactory.rs

@@ -1412,7 +1412,6 @@ mod tests {
     use crate::test_utils::{get_chat_msg, TestContext};
 
     use async_std::fs::File;
-    use pretty_assertions::assert_eq;
 
     #[test]
     fn test_render_email_address() {

src/peerstate.rs

@@ -524,7 +524,6 @@ pub(crate) async fn deduplicate_peerstates(sql: &Sql) -> Result<()> {
 mod tests {
     use super::*;
     use crate::test_utils::alice_keypair;
-    use pretty_assertions::assert_eq;
 
     #[async_std::test]
     async fn test_peerstate_save_to_db() {