Pinned Composer version in all PHP docker images

images/php/8.1/Dockerfile

@@ -93,7 +93,7 @@ RUN git clone --branch v0.4.15 --depth=1 https://github.com/NoiseByNorthwest/php
     && make install
 
 RUN curl -sS https://getcomposer.org/installer | \
-  php -- --install-dir=/usr/local/bin --filename=composer
+  php -- --version=2.6.6 --install-dir=/usr/local/bin --filename=composer
 
 COPY conf/blackfire.ini $PHP_INI_DIR/conf.d/blackfire.ini
 COPY conf/spx.ini $PHP_INI_DIR/conf.d/spx.ini

images/php/8.3/Dockerfile

@@ -104,7 +104,7 @@ RUN git clone --branch v0.4.15 --depth=1 https://github.com/NoiseByNorthwest/php
     && make install
 
 RUN curl -sS https://getcomposer.org/installer | \
-  php -- --install-dir=/usr/local/bin --filename=composer
+  php -- --version=2.6.6 --install-dir=/usr/local/bin --filename=composer
 
 COPY conf/blackfire.ini $PHP_INI_DIR/conf.d/blackfire.ini
 COPY conf/spx.ini $PHP_INI_DIR/conf.d/spx.ini