Bump axios related dependencies

Dependabot bumped axios from 0.19.2 to 0.21.1 in #434, but the older
version of axios remained in the lockfile. Using `yarn why axios`, we
can see that the older version is a dependency of `@percy/agent`,
`backport`, and `chromedriver`. By bumping each of these to the latest
compatible versions we can properly eliminate the old version of axios
from the lockfile.

Signed-off-by: Tommy Markley <markleyt@amazon.com>

package.json

@@ -245,7 +245,7 @@
     "@osd/utility-types": "1.0.0",
     "@microsoft/api-documenter": "7.7.2",
     "@microsoft/api-extractor": "7.7.0",
-    "@percy/agent": "^0.26.0",
+    "@percy/agent": "^0.28.6",
     "@testing-library/dom": "^7.24.2",
     "@testing-library/jest-dom": "^5.11.4",
     "@testing-library/react": "^11.0.4",
@@ -348,12 +348,12 @@
     "babel-eslint": "^10.0.3",
     "babel-jest": "^26.3.0",
     "babel-plugin-istanbul": "^6.0.0",
-    "backport": "5.4.1",
+    "backport": "^5.6.6",
     "brace": "0.11.1",
     "chai": "3.5.0",
     "chance": "1.0.18",
     "cheerio": "0.22.0",
-    "chromedriver": "^87.0.0",
+    "chromedriver": "^88.0.0",
     "classnames": "2.2.6",
     "compare-versions": "3.5.1",
     "d3": "3.5.17",