Updated readme.

Author: pcpl2

Readme.md

@@ -59,17 +59,17 @@ TARGET_FORMATS=jpg,webp,avif
 
 ### Config values description
 
-| Configuration key | Default value | Description |
-| ----------- | --------- | ----------- |
-| API_KEY |  | Api key for upload images. If not set application throw error. |
-| API_KEY_HEADER |  | Header name for an API key in the request. If not set application throw error. |
-| CONVERT_TO_RES | 1024x720,800x600 | List of resolutions to which images will be converted. |
-| TARGET_FORMATS | jpg | List of target image formats. Current supported is `jpg`,`webp`,`avif` |
-| MAX_FILE_SIZE | 10 | Maximum size of the file sent to the application in megabytes. |
-| CACHE_CONTROL_HEADER | max-age=180, public | Sets HTTP header `Cache-Control` for control caching in browsers. [More information](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Cache-Control) |
-| AVIF_QUALITY | 70.0 | Quality `1..=100`. Panics if out of range. |
-| AVIF_SPEED | 6 | 1 = very very slow, but max compression.<br>10 = quick, but larger file sizes and lower quality.<br><br>Panics if outside `1..=10`.  |
-| CACHE_TIME | 30 | Image cache lifetime set in minutes. **(Not implemented yet)** |
+| Configuration key | Required | Default value | Description |
+| ----------- | ---- | --------- | ----------- |
+| API_KEY | Yes |  | Api key for upload images. If not set application throw error. |
+| API_KEY_HEADER | Yes |  | Header name for an API key in the request. If not set application throw error. |
+| CONVERT_TO_RES | No | 1024x720,800x600 | List of resolutions to which images will be converted. |
+| TARGET_FORMATS | No | jpg | List of target image formats. Current supported is `jpg`,`webp`,`avif` |
+| MAX_FILE_SIZE | No | 10 | Maximum size of the file sent to the application in megabytes. |
+| CACHE_CONTROL_HEADER | No | max-age=180, public | Sets HTTP header `Cache-Control` for control caching in browsers. [More information](https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/Cache-Control) |
+| AVIF_QUALITY | No | 70.0 | Quality `1..=100`. Panics if out of range. |
+| AVIF_SPEED | No | 6 | 1 = very very slow, but max compression.<br>10 = quick, but larger file sizes and lower quality.<br><br>Panics if outside `1..=10`.  |
+| CACHE_TIME | No | 30 | Image cache lifetime set in minutes. **(Not implemented yet)** |
 
 ### Volumes configuration in container