dev_build.py: fix for cargo workspace changes

Even when doing `cd tool/microkit` and then `cargo build`
this will instead generate a `target/` directory in the root
directory, so we need to update dev_build.py to handle that.

Signed-off-by: Ivan Velickovic <i.velickovic@unsw.edu.au>

Author: Ivan-Velickovic

dev_build.py

@@ -90,7 +90,7 @@ def main():
     make_env["MICROKIT_BOARD"] = args.board
     make_env["MICROKIT_CONFIG"] = args.config
     make_env["MICROKIT_SDK"] = str(release)
-    make_env["MICROKIT_TOOL"] = (CWD / "tool/microkit/target/release/microkit").absolute()
+    make_env["MICROKIT_TOOL"] = (CWD / "target/release/microkit").absolute()
     make_env["LLVM"] = str(args.llvm)
 
     # Choose the makefile based on the `--example-from-sdk` command line flag