Version upgrade to 2.0 (#4252)

# Description of Changes

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here. -->

- Version upgrade to 2.0.

# API and ABI breaking changes

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corresponding GitHub label. -->

# Expected complexity level and risk

1 - this is just a version bump

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# Testing

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reviewers to do,
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- [x] License file has been updated
- [x] CI passing

---------

Signed-off-by: John Detter <4099508+jdetter@users.noreply.github.com>

Author: jdetter

.github/workflows/ci.yml

@@ -32,6 +32,7 @@ jobs:
     timeout-minutes: 120
     env:
       CARGO_TARGET_DIR: ${{ github.workspace }}/target
+      SPACETIMEDB_CPP_DIR: ${{ github.workspace }}/crates/bindings-cpp
     steps:
       - name: Find Git ref
         env: