Stop testing unsupported versions

See https://www.postgresql.org/support/versioning/
See https://mariadb.com/kb/en/mariadb-server/

.travis.yml

@@ -146,11 +146,6 @@ jobs:
         - docker
       before_script:
         - bash ./tests/travis/install-mysql-8.0.sh
-    - stage: Test
-      php: 7.3
-      env: DB=mariadb MARIADB_VERSION=10.0 COVERAGE=yes
-      addons:
-        mariadb: 10.0
     - stage: Test
       php: 7.3
       env: DB=mariadb.docker MARIADB_VERSION=10.1 COVERAGE=yes
@@ -168,11 +163,6 @@ jobs:
       env: DB=mariadb MARIADB_VERSION=10.3 COVERAGE=yes
       addons:
         mariadb: 10.3
-    - stage: Test
-      php: 7.3
-      env: DB=mariadb.mysqli MARIADB_VERSION=10.0 COVERAGE=yes
-      addons:
-        mariadb: 10.0
     - stage: Test
       php: 7.3
       env: DB=mariadb.mysqli.docker MARIADB_VERSION=10.1 COVERAGE=yes
@@ -190,20 +180,6 @@ jobs:
       env: DB=mariadb.mysqli MARIADB_VERSION=10.3 COVERAGE=yes
       addons:
         mariadb: 10.3
-    - stage: Test
-      php: 7.3
-      env: DB=pgsql POSTGRESQL_VERSION=9.2 COVERAGE=yes
-      services:
-        - postgresql
-      addons:
-        postgresql: "9.2"
-    - stage: Test
-      php: 7.3
-      env: DB=pgsql POSTGRESQL_VERSION=9.3 COVERAGE=yes
-      services:
-        - postgresql
-      addons:
-        postgresql: "9.3"
     - stage: Test
       php: 7.3
       env: DB=pgsql POSTGRESQL_VERSION=9.4 COVERAGE=yes