Add GHC 8.10.1 to .travis.yml build.

Author: LeifW

.travis.yml

@@ -37,6 +37,9 @@ jobs:
     - compiler: ghcjs-8.4
       addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu bionic main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"},{"sourceline":"deb http://ppa.launchpad.net/hvr/ghcjs/ubuntu bionic main"},{"sourceline":"deb https://deb.nodesource.com/node_10.x bionic main","key_url":"https://deb.nodesource.com/gpgkey/nodesource.gpg.key"}],"packages":["ghcjs-8.4","cabal-install-3.0","ghc-8.4.4","nodejs"]}}
       os: linux
+    - compiler: ghc-8.10.1
+      addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu bionic main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.10.1","cabal-install-3.2"]}}
+      os: linux
     - compiler: ghc-8.8.2
       addons: {"apt":{"sources":[{"sourceline":"deb http://ppa.launchpad.net/hvr/ghc/ubuntu bionic main","key_url":"https://keyserver.ubuntu.com/pks/lookup?op=get&search=0x063dab2bdc0b3f9fcebc378bff3aeacef6f88286"}],"packages":["ghc-8.8.2","cabal-install-3.0"]}}
       os: linux