[release] src/goTools: update min/latest gopls version to 0.6.6

From https://proxy.golang.org/golang.org/x/tools/gopls/@v/v0.6.6.info
{"Version":"v0.6.6","Time":"2021-02-22T19:32:25Z"}

For #1300

Change-Id: I2d4059d913d0e0fa70b908292ab7e179ee741759
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/301149
Trust: Hyang-Ah Hana Kim <[email protected]>
Reviewed-by: Rebecca Stambler <[email protected]>
(cherry picked from commit 90370ab)
Reviewed-on: https://go-review.googlesource.com/c/vscode-go/+/301151
Run-TryBot: Hyang-Ah Hana Kim <[email protected]>
TryBot-Result: kokoro <[email protected]>

Author: hyangah

src/goTools.ts

@@ -361,10 +361,10 @@ export const allToolsInformation: { [key: string]: Tool } = {
 		isImportant: true,
 		description: 'Language Server from Google',
 		minimumGoVersion: semver.coerce('1.12'),
-		latestVersion: semver.coerce('0.6.4'),
-		latestVersionTimestamp: moment('2021-01-19', 'YYYY-MM-DD'),
-		latestPrereleaseVersion: semver.coerce('0.6.4'),
-		latestPrereleaseVersionTimestamp: moment('2021-01-19', 'YYYY-MM-DD')
+		latestVersion: semver.coerce('0.6.6'),
+		latestVersionTimestamp: moment('2021-02-22', 'YYYY-MM-DD'),
+		latestPrereleaseVersion: semver.coerce('0.6.6'),
+		latestPrereleaseVersionTimestamp: moment('2021-02-22', 'YYYY-MM-DD')
 	},
 	'dlv': {
 		name: 'dlv',