Update Rust crate base64 to 0.13

Author: renovate-bot

api/Cargo.toml

@@ -17,7 +17,7 @@ failure = "0.1.8"
 serde = "1.0"
 serde_derive = "1.0"
 serde_json = "1.0"
-base64 = "0.9"
+base64 = "0.13"
 
 [dev-dependencies]
 serde_test = "1.0"

holding/Cargo.toml

@@ -27,7 +27,7 @@ futures = "0.1.21"
 tokio = "0.1.7"
 tokio-core = "0.1.18"
 failure = "0.1.8"
-base64 = "0.9"
+base64 = "0.13"
 log = "0.4"
 openssl = "0.10"
 kubernetes_api = { path = "../api" }