build(deps): bump golang.org/x/sys from 0.26.0 to 0.28.0

Bumps [golang.org/x/sys](https://github.com/golang/sys) from 0.26.0 to 0.28.0.
- [Commits](golang/sys@v0.26.0...v0.28.0)

---
updated-dependencies:
- dependency-name: golang.org/x/sys
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

go.mod

@@ -2,4 +2,4 @@ module github.com/photostorm/gatt
 
 go 1.13
 
-require golang.org/x/sys v0.26.0
+require golang.org/x/sys v0.28.0

go.sum

@@ -1,2 +1,2 @@
-golang.org/x/sys v0.26.0 h1:KHjCJyddX0LoSTb3J+vWpupP9p0oznkqVk/IfjymZbo=
-golang.org/x/sys v0.26.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
+golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
+golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=