integer-gmp: Bump version and add changelog entry

libraries/integer-gmp/changelog.md

 # Changelog for [`integer-gmp` package](http://hackage.haskell.org/package/integer-gmp)
 
+## 1.0.3.0 *January 2019*
+
+  * Bundled with GHC 8.10.1
+
+  * Documentation changes
+
 ## 1.0.2.0 *April 2018*
 
   * Bundled with GHC 8.4.2

libraries/integer-gmp/integer-gmp.cabal

 cabal-version:       2.0
 name:                integer-gmp
-version:             1.0.2.0
+version:             1.0.3.0
 
 synopsis:            Integer library based on GMP
 license:             BSD3