Auto merge of #2602 - JohnTitor:parking-lot, r=jtgeibel

Update `parking_lot` to 0.11

This makes one dependency duplication but it'll be resolved once we drop rand 0.6.

log:
```
    Adding cloudabi v0.1.0
    Adding instant v0.1.5
    Updating lock_api v0.3.4 -> v0.4.0
    Updating parking_lot v0.10.2 -> v0.11.0
    Updating parking_lot_core v0.7.2 -> v0.8.0
    Updating r2d2 v0.8.8 -> v0.8.9
    Updating scheduled-thread-pool v0.2.4 -> v0.2.5
```

r? @jtgeibel

Author: bors

Cargo.lock

@@ -59,7 +59,7 @@ scheduled-thread-pool = "0.2.0"
 derive_deref = { version = "1.0.0", git = "https://github.com/azriel91/derive_deref.git", rev = "63527ab" }
 reqwest = { version = "0.10", features = ["blocking", "gzip", "json"] }
 tempfile = "3"
-parking_lot = "0.10"
+parking_lot = "0.11"
 jemallocator = { version = "0.3", features = ['unprefixed_malloc_on_supported_platforms', 'profiling'] }
 
 lettre = "0.9"