Modernize Perl and PostgreSQL versions

Add PostgreSQL 11, 12, and 13. Run tests on focal. Upgrade to Perl 5.30,
and bump lowest supported Perl version to 5.14 (oldest version supported
on focal).

Author: df7cb

.travis.yml

@@ -2,6 +2,9 @@
 ---
 # versions to run on
 env:
+  - PGVERSION=13
+  - PGVERSION=12
+  - PGVERSION=11
   - PGVERSION=10
   - PGVERSION=9.6
   - PGVERSION=9.5
@@ -12,25 +15,20 @@ env:
   - PGVERSION=9.0
   - PGVERSION=8.4
 
-dist: trusty
+dist: focal
 sudo: required
 language: perl
 perl:
-  - '5.8' # 5.8.8 is shipped with RHEL 5, also oldest version supported by Travis
-  - '5.24'
+  - '5.30'
+  - '5.14' # 5.14 is shipped with Ubuntu precise (12.04), also oldest version supported by Travis on focal
 
 before_install:
   - sudo apt-get -qq update
 
 install:
-  # install PostgreSQL $PGVERSION if not there yet
-  - |
-    if [ ! -x /usr/lib/postgresql/$PGVERSION/bin/postgres ]; then
-      sudo apt-get install postgresql-common
-      sudo /etc/init.d/postgresql stop # travis wants only one version running
-      sudo apt-get install postgresql-contrib-$PGVERSION
-    fi
-  - sudo /etc/init.d/postgresql stop
+  # upgrade postgresql-common for new apt.postgresql.org.sh
+  - sudo apt-get install -y postgresql-common
+  - sudo /usr/share/postgresql-common/pgdg/apt.postgresql.org.sh -p -v $PGVERSION -i
   - pg_lsclusters
   - dpkg -l postgresql\* | cat
   - printenv | sort