Lock update operations to prevent race in between updates.

[jaer-tsun]

What this PR does / why we need it:
Update operations should've been locked to prevent a race between other operations.

e.g.

namespace updates

npm deletes namespace
network policy updates
npm deletes network policy
npm adds network policy (fails because namespace was not created yet)
...
npm add namespace

[matmerr]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 1 pipeline(s).