Define arch for all workflows on aarch64

Author: asenyaev

travis_config.sh

@@ -36,7 +36,8 @@ else
   echo "    > Linux environment "
   export LD_LIBRARY_PATH=$LD_LIBRARY_PATH:/opt/Qt5.15.0/lib
   export MAKEFLAGS="-j$(grep -E '^processor[[:space:]]*:' /proc/cpuinfo | wc -l)"
-  if [[ $PLAT == 'aarch64' ]]; then
+  CURRENT_ARCH=$(uname -m)
+  if [[ $CURRENT_ARCH == 'aarch64' ]]; then
     # To avoid network issues with pypi.org on OpenCV CN machines
     export PIP_INDEX_URL=https://pypi.tuna.tsinghua.edu.cn/simple
     echo "Running for linux aarch64"