build(deps): bump github.com/shirou/gopsutil/v3 from 3.21.3 to 3.21.4

Bumps [github.com/shirou/gopsutil/v3](https://github.com/shirou/gopsutil) from 3.21.3 to 3.21.4.
- [Release notes](https://github.com/shirou/gopsutil/releases)
- [Commits](shirou/gopsutil@v3.21.3...v3.21.4)

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

go.mod

@@ -20,7 +20,7 @@ require (
 	github.com/jmoiron/sqlx v1.3.3
 	github.com/opentracing/opentracing-go v1.2.0
 	github.com/rollbar/rollbar-go v1.3.0
-	github.com/shirou/gopsutil/v3 v3.21.3
+	github.com/shirou/gopsutil/v3 v3.21.4
 	github.com/skip2/go-qrcode v0.0.0-20200617195104-da1b6568686e
 	github.com/slack-go/slack v0.9.0
 	github.com/sourcegraph/checkup v1.0.1-0.20200721114922-77e7567835d4