travis-ci: update distributives and repositories

* Deploy packages for CentOS 8, Fedora 31 and Ubuntu Eoan.
* Test on tarantool 2.3 and 2.4.
* Deploy packages to 2.3 and 2.4 repositories.

Author: Totktonada

.travis.yml

@@ -47,6 +47,10 @@ _packpack: &packpack
       repository: "2x"
     - <<: *deploy_to_packagecloud
       repository: "2_2"
+    - <<: *deploy_to_packagecloud
+      repository: "2_3"
+    - <<: *deploy_to_packagecloud
+      repository: "2_4"
 
 jobs:
   include:
@@ -56,6 +60,10 @@ jobs:
       script: ./test.sh
     - env: VERSION=2_2
       script: ./test.sh
+    - env: VERSION=2_3
+      script: ./test.sh
+    - env: VERSION=2_4
+      script: ./test.sh
 
     - stage: deploy
       name: Publish rockspecs
@@ -77,12 +85,16 @@ jobs:
       env: OS=el DIST=6
     - <<: *packpack
       env: OS=el DIST=7
+    - <<: *packpack
+      env: OS=el DIST=8
     - <<: *packpack
       env: OS=fedora DIST=28
     - <<: *packpack
       env: OS=fedora DIST=29
     - <<: *packpack
       env: OS=fedora DIST=30
+    - <<: *packpack
+      env: OS=fedora DIST=31
     - <<: *packpack
       env: OS=ubuntu DIST=trusty
     - <<: *packpack
@@ -91,6 +103,8 @@ jobs:
       env: OS=ubuntu DIST=bionic
     - <<: *packpack
       env: OS=ubuntu DIST=disco
+    - <<: *packpack
+      env: OS=ubuntu DIST=eoan
     - <<: *packpack
       env: OS=debian DIST=jessie
     - <<: *packpack