Bump github.com/signalfx/signalfx-go from 1.37.0 to 1.40.0

Bumps [github.com/signalfx/signalfx-go](https://github.com/signalfx/signalfx-go) from 1.37.0 to 1.40.0.
- [Release notes](https://github.com/signalfx/signalfx-go/releases)
- [Changelog](https://github.com/signalfx/signalfx-go/blob/master/CHANGELOG.md)
- [Commits](signalfx/signalfx-go@V1.37.0...v1.40.0)

---
updated-dependencies:
- dependency-name: github.com/signalfx/signalfx-go
  dependency-type: direct:production
  update-type: version-update:semver-minor
...

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

go.mod

@@ -4,7 +4,7 @@ go 1.21
 
 require (
 	github.com/gorilla/websocket v1.5.3
-	github.com/signalfx/signalfx-go v1.37.0
+	github.com/signalfx/signalfx-go v1.40.0
 	github.com/stretchr/testify v1.9.0
 )
 

go.sum

@@ -9,8 +9,8 @@ github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
-github.com/signalfx/signalfx-go v1.37.0 h1:AtCvcW9VGoVUnCVcoHLbRD5QUsMpy1SnViJN+jKGBU8=
-github.com/signalfx/signalfx-go v1.37.0/go.mod h1:aVrA69k02raBhDtIL1l+KBu+H5eEmS5b0IFbqgKh7eg=
+github.com/signalfx/signalfx-go v1.40.0 h1:1A7zIiD4uKtafOETHZ60n+nsLrHfxO7rAv0UqWHWIV4=
+github.com/signalfx/signalfx-go v1.40.0/go.mod h1:aVrA69k02raBhDtIL1l+KBu+H5eEmS5b0IFbqgKh7eg=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=