CI: Travis: explicitly state the builds

M  .travis.yml

.travis.yml

@@ -96,8 +96,35 @@ env:
     - GHCVERSION=ghc8101
     - GHCVERSION=ghcjs
 
-#  2020-05-25: NOTE: We still yet to build this in `master`
+#  2020-05-26: NOTE: Currently newest Travis dist Ubuntu 18.04 bionic
+# NOTE: {os} x {jobs} + {jobs:include} - {jobs:exclude} = {build matrix}
 jobs:
+  include:
+    - name: GHC 8.4.4 Linux
+      env: GHCVERSION=ghc844
+      os: linux
+      dist: bionic
+    - name: GHC 8.6.5 Linux
+      env:
+        - GHCVERSION=ghc865
+        - buildFromSdist=true
+      os: linux
+      dist: bionic
+    - name: GHC 8.8.3 macOS
+      env:
+        - GHCVERSION=ghc883
+        - buildFromSdist=true
+      os: osx
+    - name: GHC 8.10.1 Linux
+      env:
+        - GHCVERSION=ghc8101
+      os: linux
+      dist: bionic
+    - name: GHCJS Linux
+      env:
+        - GHCVERSION=ghcjs
+      os: linux
+      dist: bionic
   allow_failures:
     - env: GHCVERSION=ghcjs
     - env: GHCVERSION=ghc8101