Update composer Docker tag to v2.6.6 (#568)

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This PR contains the following updates:

| Package | Type | Update | Change |
|---|---|---|---|
| composer | final | patch | `2.6.5` -> `2.6.6` |

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Dockerfile.php-cli

@@ -1,6 +1,6 @@
 FROM lendableuk/php-fpm-alpine:8.1.11-alpine3.15
 
-COPY --from=composer:2.6.5 /usr/bin/composer /usr/bin/composer
+COPY --from=composer:2.6.6 /usr/bin/composer /usr/bin/composer
 
 COPY . /app
 WORKDIR /app