Apply SVG optimization recursively to image subfolders (#411)

* Update svgo to latest

* Run SVG optimization recursively

* Optimize images

* Update CHANGELOG.md

* Update dependencies for 9.0 release (#412)

* Use non-abbreviated name for command flags

Co-authored-by: Zach Margolis <zachmargolis@users.noreply.github.com>

---------

Co-authored-by: Zach Margolis <zachmargolis@users.noreply.github.com>

CHANGELOG.md

@@ -31,18 +31,23 @@
     - `gray-50` (use `base` instead)
     - `gray-70` (use `base-darker` instead)
     - `gray-90` (use `base-darkest` instead)
-- Remove images not integral to the design system. If you use any of these images, consider proposed alternatives below, or copy [the image from the previous release](https://github.com/18F/identity-design-system/tree/v8.1.2/src/img) into your project:
-  - `illustrations/fail.svg` (legacy alert icon, new alert icons will be introduced in a future release)
-  - `illustrations/security-key.svg`
-  - `angle-arrow-down-white-hover.svg` (use `expand_more` icon instead)
-  - `angle-arrow-down-white.svg` (use `expand_more` icon instead)
-  - `angle-arrow-down.svg` (use `expand_more` icon instead)
-  - `angle-arrow-up-white-hover.svg` (use `expand_less` icon instead)
-  - `angle-arrow-up-white.svg` (use `expand_less` icon instead)
-  - `angle-arrow-up.svg` (use `expand_less` icon instead)
-  - `close-primary.svg` (use `close` icon instead)
-  - `close.svg` (use `close` icon instead)
-  - `hero.png`
+- Remove images not integral to the design system. ([#410](https://github.com/18F/identity-design-system/pull/410))
+  - If you use any of these images, consider proposed alternatives below, or copy [the image from the previous release](https://github.com/18F/identity-design-system/tree/v8.1.2/src/img) into your project:
+    - `illustrations/fail.svg` (legacy alert icon, new alert icons will be introduced in a future release)
+    - `illustrations/security-key.svg`
+    - `angle-arrow-down-white-hover.svg` (use `expand_more` icon instead)
+    - `angle-arrow-down-white.svg` (use `expand_more` icon instead)
+    - `angle-arrow-down.svg` (use `expand_more` icon instead)
+    - `angle-arrow-up-white-hover.svg` (use `expand_less` icon instead)
+    - `angle-arrow-up-white.svg` (use `expand_less` icon instead)
+    - `angle-arrow-up.svg` (use `expand_less` icon instead)
+    - `close-primary.svg` (use `close` icon instead)
+    - `close.svg` (use `close` icon instead)
+    - `hero.png`
+
+### Improvements
+
+- Optimize images to reduce their size. ([#411](https://github.com/18F/identity-design-system/pull/411))
 
 ### New Features
 

Makefile

@@ -29,7 +29,7 @@ typecheck:
 	npm run typecheck
 
 optimize-svg:
-	$(NODE_BIN)/svgo --config svgo.config.js -f src/img
+	$(NODE_BIN)/svgo --config svgo.config.js --recursive --folder src/img
 
 optimize-assets: optimize-svg