Azure Pipelines: Use "python3" instead of "python" on macOS

63b841efc01897bb26b5bb969306e9bf33c37823 was not the solution, the error is the print statement itself.

Python 2 is probably used by default and thus "python" is an alias to it.

.ci/azure-pipelines/macos_build.sh

@@ -1,7 +1,7 @@
 #!/bin/bash
 
 if [[ "${#SE_BUILD_NUMBER_TOKEN}" -eq 64 ]]; then
-	VERSION=$(python "version.py")
+	VERSION=$(python3 "version.py")
 	BUILD_NUMBER=$(curl "https://softether.network/get-build-number?commit=${BUILD_SOURCEVERSION}&version=${VERSION}&token=${SE_BUILD_NUMBER_TOKEN}")
 else
 	BUILD_NUMBER=0