Update build-pio.sh

Author: me-no-dev

travis/build-pio.sh

@@ -6,7 +6,7 @@ echo -e "travis_fold:start:install_pio"
 pip install -U platformio
 if [ $? -ne 0 ]; then exit 1; fi
 
-python -m platformio lib --storage-dir $PWD
+python -m platformio lib --storage-dir $TRAVIS_BUILD_DIR install
 if [ $? -ne 0 ]; then exit 1; fi
 
 python -m platformio lib -g install https://github.com/bblanchon/ArduinoJson.git
@@ -24,7 +24,7 @@ if [ $? -ne 0 ]; then exit 1; fi
 echo -e "travis_fold:end:install_pio"
 
 echo -e "travis_fold:start:test_pio"
-for EXAMPLE in $PWD/examples/*/*.ino; do
+for EXAMPLE in $TRAVIS_BUILD_DIR/examples/*/*.ino; do
     python -m platformio ci $EXAMPLE -l '.' -b $BOARD
     if [ $? -ne 0 ]; then exit 1; fi
 done