Update Rust crate diesel to 1.4.8

Author: renovate-bot

Cargo.toml

@@ -50,7 +50,7 @@ cookie = { version = "0.15", features = ["secure"] }
 dashmap = { version = "4.0.2", features = ["raw-api"] }
 derive_deref = "1.1.1"
 dialoguer = "0.9"
-diesel = { version = "1.4.0", features = ["postgres", "serde_json", "chrono", "r2d2"] }
+diesel = { version = "1.4.8", features = ["postgres", "serde_json", "chrono", "r2d2"] }
 diesel_full_text_search = "1.0.0"
 diesel_migrations = { version = "1.3.0", features = ["postgres"] }
 dotenv = "0.15"
@@ -97,6 +97,6 @@ tokio = "1.5.0"
 tower-service = "0.3.0"
 
 [build-dependencies]
-diesel = { version = "1.3.0", features = ["postgres"] }
+diesel = { version = "1.4.8", features = ["postgres"] }
 diesel_migrations = { version = "1.3.0", features = ["postgres"] }
 dotenv = "0.15"