Fix php-fpm build fail (php5)

pecl redis no longer support php5

Author: akccakcctw

php-fpm/Dockerfile

@@ -197,9 +197,13 @@ ARG INSTALL_PHPREDIS=false
 
 RUN if [ ${INSTALL_PHPREDIS} = true ]; then \
     # Install Php Redis Extension
-    printf "\n" | pecl install -o -f redis \
-    &&  rm -rf /tmp/pear \
-    &&  docker-php-ext-enable redis \
+    if [ $(php -r "echo PHP_MAJOR_VERSION;") = "5" ]; then \
+      pecl install -o -f redis-4.3.0; \
+    else \
+      pecl install -o -f redis; \
+    fi \
+    && rm -rf /tmp/pear \
+    && docker-php-ext-enable redis \
 ;fi
 
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