Photos: Update block caption colour; see #459.

photos/blocks.css

@@ -164,7 +164,6 @@ p.has-drop-cap:not(:focus):first-letter {
 }
 
 .wp-block-image figcaption {
-	color: #606060;
 	font-size: 0.8em;
 	margin-top: 0;
 	padding-top: 0.625em;
@@ -177,10 +176,8 @@ p.has-drop-cap:not(:focus):first-letter {
 }
 
 /* Captions */
-.wp-block-image figcaption,
-.wp-block-audio figcaption,
-.wp-block-video figcaption {
-	color: #606060;
+[class^="wp-block-"]:not(.wp-block-gallery) figcaption {
+	color: inherit;
 }
 
 /* Blockquotes*/