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

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

.travis.yml

@@ -1,5 +1,5 @@
 language: c
-dist: xenial
+dist: bionic
 env:
   global:
     secure: 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
@@ -39,7 +39,7 @@ matrix:
            NPROC="nproc" CFLAGS="-O3"
     - env: CONFIG="--with-openssl --prefix=/usr --with-tpm2 --enable-test-coverage"
            TARGET="install" NPROC="nproc"
-      dist: bionic
+      dist: focal
       before_script:
       - sudo pip install cpp-coveralls
       script:
@@ -62,7 +62,7 @@ matrix:
         cpp-coveralls -b src -e tests -e swtpm --gcov-options '\-lp'
     - env: CONFIG="--with-openssl --prefix=/usr --with-tpm2 --enable-test-coverage --disable-use-openssl-functions"
            TARGET="install" NPROC="nproc"
-      dist: bionic
+      dist: focal
       script:
         ./autogen.sh ${CONFIG} &&
         sudo make -j$(nproc) ${TARGET} &&