Bump is-svg and postcss-svgo

Removes [is-svg](https://github.com/sindresorhus/is-svg). It's no longer used after updating ancestor dependency [postcss-svgo](https://github.com/cssnano/cssnano). These dependencies need to be updated together.


Removes `is-svg`

Updates `postcss-svgo` from 4.0.1 to 4.0.3
- [Release notes](https://github.com/cssnano/cssnano/releases)
- [Commits](cssnano/cssnano@4.0.1...4.0.3)

---
updated-dependencies:
- dependency-name: is-svg
  dependency-type: indirect
- dependency-name: postcss-svgo
  dependency-type: indirect
...

Signed-off-by: dependabot[bot] <support@github.com>

yarn.lock

@@ -4992,11 +4992,6 @@ hsla-regex@^1.0.0:
   resolved "https://registry.yarnpkg.com/hsla-regex/-/hsla-regex-1.0.0.tgz#c1ce7a3168c8c6614033a4b5f7877f3b225f9c38"
   integrity sha1-wc56MWjIxmFAM6S194d/OyJfnDg=
 
-html-comment-regex@^1.1.0:
-  version "1.1.2"
-  resolved "https://registry.yarnpkg.com/html-comment-regex/-/html-comment-regex-1.1.2.tgz#97d4688aeb5c81886a364faa0cad1dda14d433a7"
-  integrity sha512-P+M65QY2JQ5Y0G9KKdlDpo0zK+/OHptU5AaBwUfAIDJZk1MYf32Frm84EcOytfJE0t5JvkAnKlmjsXDnWzCJmQ==
-
 html-element-map@^1.0.0:
   version "1.1.0"
   resolved "https://registry.yarnpkg.com/html-element-map/-/html-element-map-1.1.0.tgz#e5aab9a834caf883b421f8bd9eaedcaac887d63c"
@@ -5677,13 +5672,6 @@ is-subset@^0.1.1:
   resolved "https://registry.yarnpkg.com/is-subset/-/is-subset-0.1.1.tgz#8a59117d932de1de00f245fcdd39ce43f1e939a6"
   integrity sha1-ilkRfZMt4d4A8kX83TnOQ/HpOaY=
 
-is-svg@^3.0.0:
-  version "3.0.0"
-  resolved "https://registry.yarnpkg.com/is-svg/-/is-svg-3.0.0.tgz#9321dbd29c212e5ca99c4fa9794c714bcafa2f75"
-  integrity sha512-gi4iHK53LR2ujhLVVj+37Ykh9GLqYHX6JOVXbLAucaG/Cqw9xwdFOjDM2qeifLs1sF1npXXFvDu0r5HNgCMrzQ==
-  dependencies:
-    html-comment-regex "^1.1.0"
-
 is-symbol@^1.0.2:
   version "1.0.2"
   resolved "https://registry.yarnpkg.com/is-symbol/-/is-symbol-1.0.2.tgz#a055f6ae57192caee329e7a860118b497a950f38"
@@ -8395,11 +8383,10 @@ postcss-selector-parser@^5.0.0, postcss-selector-parser@^5.0.0-rc.3, postcss-sel
     uniq "^1.0.1"
 
 postcss-svgo@^4.0.2:
-  version "4.0.2"
-  resolved "https://registry.yarnpkg.com/postcss-svgo/-/postcss-svgo-4.0.2.tgz#17b997bc711b333bab143aaed3b8d3d6e3d38258"
-  integrity sha512-C6wyjo3VwFm0QgBy+Fu7gCYOkCmgmClghO+pjcxvrcBKtiKt0uCF+hvbMO1fyv5BMImRK90SMb+dwUnfbGd+jw==
+  version "4.0.3"
+  resolved "https://registry.yarnpkg.com/postcss-svgo/-/postcss-svgo-4.0.3.tgz#343a2cdbac9505d416243d496f724f38894c941e"
+  integrity sha512-NoRbrcMWTtUghzuKSoIm6XV+sJdvZ7GZSc3wdBN0W19FTtp2ko8NqLsgoh/m9CzNhU3KLPvQmjIwtaNFkaFTvw==
   dependencies:
-    is-svg "^3.0.0"
     postcss "^7.0.0"
     postcss-value-parser "^3.0.0"
     svgo "^1.0.0"