加入awebp编码支持

_locales/en.json

@@ -22,6 +22,7 @@
         "thumbnailTitle": "Set the current frame as this item's 400×400 custom thumbnail",
         "animatedThumbnailTitle": "Generate animated thumbnail",
         "animatedThumbnailNote": "This replaces the current thumbnail and cannot be undone by the plugin. Frame count, color precision and detail are reduced first; if needed, dimensions are reduced progressively from 400×400.",
+        "animatedFormat": "Output format",
         "animatedRange": "Animation range",
         "animatedStart": "Start",
         "animatedEnd": "End",
@@ -30,6 +31,7 @@
         "animatedMaxSize": "File size limit",
         "animatedInvalidSize": "Enter a whole number between 50 and 10240 KB",
         "animatedCompressing": "Compressing animated thumbnail {current}/{total}…",
+        "animatedWebpUnavailable": "This environment cannot encode WebP. Choose APNG instead.",
         "animatedCannotFit": "The animation cannot be reduced to {target} KB (minimum about {actual} KB). Increase the limit or shorten the frame range.",
         "qualityLow": "Low",
         "qualityMedium": "Medium",