Fix incorrect casing on getCacheKeyForURL

[philipwalton]

R: @jeffposnick

Weston noticed this was incorrect in our release notes, and when I did a search through the project I found these four incorrect instances.

[workbox-pr-bot]

PR-Bot Size Plugin

Changed File Sizes

File	Before	After	Change	GZipped
packages/workbox-background-sync/build/workbox-background-sync.prod.js	3.51 KB	3.61 KB	+3%	1.56 KB
packages/workbox-build/build/index.js	4.02 KB	3.64 KB	-9%	1.36 KB
packages/workbox-cli/build/app.js	6.76 KB	5.58 KB	-17%	1.98 KB	🎉
packages/workbox-cli/build/bin.js	2.32 KB	1.16 KB	-50%	580 B	🎉
packages/workbox-core/build/workbox-core.prod.js	7.47 KB	5.43 KB	-27%	2.36 KB	🎉
packages/workbox-precaching/build/workbox-precaching.prod.js	5.80 KB	4.21 KB	-27%	1.68 KB	🎉
packages/workbox-range-requests/build/workbox-range-requests.prod.js	1.63 KB	1.52 KB	-7%	763 B
packages/workbox-routing/build/workbox-routing.prod.js	2.87 KB	3.23 KB	+13%	1.42 KB	☠️
packages/workbox-strategies/build/workbox-strategies.prod.js	5.09 KB	4.87 KB	-4%	1.19 KB
packages/workbox-streams/build/workbox-streams.prod.js	1.57 KB	1.38 KB	-12%	684 B	🎉
packages/workbox-sw/build/workbox-sw.js	1.50 KB	1.34 KB	-11%	747 B	🎉
packages/workbox-webpack-plugin/build/generate-sw.js	8.04 KB	5.29 KB	-34%	1.84 KB	🎉
packages/workbox-webpack-plugin/build/index.js	742 B	349 B	-53%	255 B	🎉
packages/workbox-webpack-plugin/build/inject-manifest.js	10.30 KB	7.22 KB	-30%	2.48 KB	🎉

New Files

File	Size	GZipped
packages/workbox-broadcast-update/build/workbox-broadcast-update.prod.js	1.86 KB	936 B
packages/workbox-expiration/build/workbox-expiration.prod.js	3.13 KB	1.29 KB
packages/workbox-google-analytics/build/workbox-offline-ga.prod.js	1.89 KB	891 B

All File Sizes

View Table

File	Before	After	Change	GZipped
packages/workbox-background-sync/build/workbox-background-sync.prod.js	3.51 KB	3.61 KB	+3%	1.56 KB
packages/workbox-broadcast-update/build/workbox-broadcast-update.prod.js		1.86 KB		936 B
packages/workbox-build/build/_types.js	41 B	41 B	0%	61 B
packages/workbox-build/build/index.js	4.02 KB	3.64 KB	-9%	1.36 KB
packages/workbox-cacheable-response/build/workbox-cacheable-response.prod.js	587 B	587 B	0%	350 B
packages/workbox-cli/build/app.js	6.76 KB	5.58 KB	-17%	1.98 KB	🎉
packages/workbox-cli/build/bin.js	2.32 KB	1.16 KB	-50%	580 B	🎉
packages/workbox-core/build/workbox-core.prod.js	7.47 KB	5.43 KB	-27%	2.36 KB	🎉
packages/workbox-expiration/build/workbox-expiration.prod.js		3.13 KB		1.29 KB
packages/workbox-google-analytics/build/workbox-offline-ga.prod.js		1.89 KB		891 B
packages/workbox-navigation-preload/build/workbox-navigation-preload.prod.js	660 B	660 B	0%	323 B
packages/workbox-precaching/build/workbox-precaching.prod.js	5.80 KB	4.21 KB	-27%	1.68 KB	🎉
packages/workbox-range-requests/build/workbox-range-requests.prod.js	1.63 KB	1.52 KB	-7%	763 B
packages/workbox-routing/build/workbox-routing.prod.js	2.87 KB	3.23 KB	+13%	1.42 KB	☠️
packages/workbox-strategies/build/workbox-strategies.prod.js	5.09 KB	4.87 KB	-4%	1.19 KB
packages/workbox-streams/build/workbox-streams.prod.js	1.57 KB	1.38 KB	-12%	684 B	🎉
packages/workbox-sw/build/workbox-sw.js	1.50 KB	1.34 KB	-11%	747 B	🎉
packages/workbox-webpack-plugin/build/generate-sw.js	8.04 KB	5.29 KB	-34%	1.84 KB	🎉
packages/workbox-webpack-plugin/build/index.js	742 B	349 B	-53%	255 B	🎉
packages/workbox-webpack-plugin/build/inject-manifest.js	10.30 KB	7.22 KB	-30%	2.48 KB	🎉

Workbox Aggregate Size Plugin

8.83KB gzip'ed (59% of limit)
22.27KB uncompressed