fix(aerospike extension): turn off build in Travis due to image version

PHP 8.0 is not supported by Aerospike. See the issue's references.

Closes #2881

workspace/Dockerfile

@@ -878,12 +878,16 @@ RUN set -xe; \
           && make install \
         ) \
       else \
+        if [ $(php -r "echo PHP_MAJOR_VERSION;") = "7" ]; then \
           ( \
               cd /tmp/aerospike-client-php/src \
               && phpize \
               && ./build.sh \
               && make install \
           ) \
+        else \
+          echo "AEROSPIKE does not support PHP 8.0"
+        fi \
       fi \
     && rm /tmp/aerospike-client-php.tar.gz \
     && echo 'extension=aerospike.so' >> /etc/php/${LARADOCK_PHP_VERSION}/cli/conf.d/aerospike.ini \