Travis: Update from xenial to bionic and from bionic to focal

Signed-off-by: Stefan Berger <stefanb@linux.ibm.com>

.travis.yml

@@ -3,7 +3,7 @@ env:
   - secure: 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
 sudo: required
 language: c
-dist: xenial
+dist: bionic
 addons:
   apt:
       packages:
@@ -28,7 +28,6 @@ addons:
         - findutils
         - gnutls-dev
         - gnutls-bin
-        - libasan2
         - softhsm2
         - libseccomp-dev
   coverity_scan:
@@ -78,7 +77,7 @@ matrix:
            CONFIG="--with-openssl --prefix=${PREFIX}"
            CHECK="distcheck"
            RUN_TEST="1"
-    - dist: bionic
+    - dist: focal
       env: PREFIX="/usr"
            CONFIG="--with-openssl --prefix=/usr --enable-test-coverage"
            SUDO="sudo"