Build PDO Firebird on Azure

Once again, this only builds the driver, all tests will be skipped.

Closes GH-6529.

azure/apt.yml

@@ -48,5 +48,6 @@ steps:
                        dovecot-pop3d \
                        dovecot-imapd \
                        sendmail \
+                       firebird-dev \
                        ${{ parameters.packages }}
     displayName: 'APT'

azure/configure.yml

@@ -62,6 +62,7 @@ steps:
         --with-kerberos \
         --with-imap-ssl \
         --with-pdo-odbc=unixODBC,/usr \
+        --with-pdo-firebird \
         --enable-werror \
         --with-config-file-path=/etc \
         --with-config-file-scan-dir=/etc/php.d