ci: actually use Bazel 2.0 in the build (#232)

Author: coryan

ci/kokoro/windows/build.bat

@@ -15,6 +15,10 @@
 REM Install Bazel using Chocolatey
 choco install -y bazel --version 2.0.0
 
+REM Change PATH to use chocolatey's version of Bazel
+set PATH=C:\ProgramData\chocolatey\bin;%PATH%
+bazel version
+
 REM Configure the environment to use MSVC 2019 and then switch to PowerShell.
 call "c:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Auxiliary\Build\vcvars64.bat"