Update CONTRIBUTING.md

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
Signed-off-by: GiannisGeo <giannisgeorgiadiis@gmail.com>

Author: Giannis-dot

CONTRIBUTING.md

@@ -177,7 +177,7 @@ During development you may want to run a single test file in isolation to avoid
 PowerShell example:
 ```powershell
 # activate virtualenv (if not already active)
-C:/Users/Giannis/OneDrive/Programming/hiero-sdk-python/.venv/Scripts/Activate.ps1
+.venv/Scripts/Activate.ps1
 
 # install test deps if needed
 python -m pip install -U pip