libraries: Update changelogs

libraries/base/changelog.md

 # Changelog for [`base` package](http://hackage.haskell.org/package/base)
 
 
-## 4.11.1.0 *TBA*
+## 4.11.1.0 *April 2018*
   * Bundled with GHC 8.4.2
 
   * Add the `readFieldHash` function to `GHC.Read` which behaves like
     `readField`, but for a field that ends with a `#` symbol (#14918).
 
-## 4.11.0.0 *TBA*
+## 4.11.0.0 *March 2018*
   * Bundled with GHC 8.4.1
 
   * `System.IO.openTempFile` is now thread-safe on Windows.

libraries/integer-gmp/changelog.md

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

libraries/template-haskell/changelog.md

 # Changelog for [`template-haskell` package](http://hackage.haskell.org/package/template-haskell)
 
-## 2.13.0.0 *TBA*
+## 2.13.0.0 *March 2018*
 
-  * Bundled with GHC *TBA*
+  * Bundled with GHC 8.4.1
 
   * `Language.Haskell.TH.FamFlavour`, which was deprecated in 2.11,
     has been removed.