Fix stackage#4312: Relax network version bound.

Issue: commercialhaskell/stackage#4312

Should be safe for us to relax bound as upstream `mysql-haskell` library has already safely relaxed its bound.

Tested with the following `stack.yaml`:

```yaml
resolver: lts-10.4
packages:
  - ./persistent
  - ./persistent-template
  - ./persistent-sqlite
  - ./persistent-test
  - ./persistent-mongoDB
  - ./persistent-mysql
  - ./persistent-mysql-haskell
  - ./persistent-postgresql
  - ./persistent-redis
  - ./persistent-qq
extra-deps:
- monad-logger-0.3.28.1
- mysql-simple-0.4.4

- mono-traversable-1.0.8.1
- unliftio-0.2.4.0
- unliftio-core-0.1.1.0
- async-2.1.1.1
- typed-process-0.2.1.0
- resourcet-1.1.11

- network-3.0.0.0
# - network-2.6.3.6
- tcp-streams-1.0.1.1
- io-streams-1.5.1.0
- mysql-haskell-0.8.4.2
```

persistent-mysql-haskell/ChangeLog.md

@@ -1,5 +1,9 @@
 # ChangeLog for `persistent-mysql-haskell`
 
+## 0.5.2
+
+- Fix [stackage#4312](https://github.com/commercialhaskell/stackage/issues/4312): Relax `network` version bound.
+
 ## 0.5.1
 
 - [#9](https://github.com/naushadh/persistent/pull/9) Add `insertEntityOnDuplicateKeyUpdate` and `insertEntityManyOnDuplicateKeyUpdate` functions

persistent-mysql-haskell/persistent-mysql-haskell.cabal

@@ -1,5 +1,5 @@
 name:            persistent-mysql-haskell
-version:         0.5.1
+version:         0.5.2
 license:         MIT
 license-file:    LICENSE
 author:          Naushadh <[email protected]>, Felipe Lessa <[email protected]>, Michael Snoyman
@@ -42,7 +42,7 @@ library
                    -- keep the following in sync with @mysql-haskell@ .cabal
                    , io-streams            >= 1.2     && < 2.0
                    , time                  >= 1.5.0
-                   , network               >= 2.3     && < 3.0
+                   , network               >= 2.3     && < 4.0
                    , tls                   >= 1.3.5   && < 1.5
     exposed-modules: Database.Persist.MySQL
     other-modules:   Database.Persist.MySQLConnectInfoShowInstance