Cache playwright browsers outside root home to allow container to run…

… as non-root (open-telemetry#1429)

Co-authored-by: Austin Parker <[email protected]>

src/loadgenerator/Dockerfile

@@ -18,5 +18,6 @@ COPY --from=builder /reqs /usr/local
 COPY ./src/loadgenerator/locustfile.py .
 COPY ./src/loadgenerator/people.json .
 ENV LOCUST_PLAYWRIGHT=1
+ENV PLAYWRIGHT_BROWSERS_PATH=/opt/pw-browsers
 RUN playwright install --with-deps chromium
 ENTRYPOINT locust