fix: bump sdk version to 3.1.1

[FelixTing]

fix: #497

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[lenny-goodell]

Why 3.1.1 and not 3.1.0?

[lenny-goodell]

Ok, I think I see that this is in prep for the future version.

[cloudxxx8]

right, we missed the version number change step in v3.1.0, and we wrote the known bug on wiki:
https://wiki.edgexfoundry.org/pages/viewpage.action?pageId=88212172#Napa(NextRelease)-KnownBugs
it only implacts the logs, and it should be a blocker for release
it's the last one we need to manually change the version number.

[lenny-goodell]

it only implacts the logs, and it should be a blocker for release

@cloudxxx8 , I assume you mean "it should not be a blocker for release", which I agree.

[cloudxxx8]

right, should not

[lindseysimple]

LGTM