use bash shell for setting env variables

With the new env variable file workflow on github,
we have to ensure that our strings are UTF-8 encoded if
using power shell. Instead, using bash keeps the action simple
and consistent across various desktop platforms.

Author: vimanyu

.github/workflows/android.yml

@@ -30,6 +30,7 @@ jobs:
           submodules: true
 
       - name: Set env variables for subsequent steps (all)
+        shell: bash
         run: |
           echo "MATRIX_UNIQUE_NAME=${{ matrix.os }}-${{ matrix.architecture }}" >> $GITHUB_ENV
           echo "GHA_INSTALL_CCACHE=1" >> $GITHUB_ENV

.github/workflows/desktop.yml

@@ -45,6 +45,7 @@ jobs:
           submodules: true
 
       - name: Set env variables for subsequent steps (all)
+        shell: bash
         run: |
           echo "VCPKG_RESPONSE_FILE=external/vcpkg_custom_data/response_files/${{ matrix.architecture }}-${{ matrix.vcpkg_triplet_suffix }}.txt" >> $GITHUB_ENV
           echo "MATRIX_UNIQUE_NAME=${{ matrix.os }}-${{ matrix.build_type }}-${{ matrix.architecture }}-${{ matrix.msvc_runtime }}" >> $GITHUB_ENV

.github/workflows/integration_tests.yml

@@ -71,9 +71,11 @@ jobs:
         if: startsWith(matrix.os, 'macos')
         run: echo "VCPKG_TRIPLET=x64-osx" >> $GITHUB_ENV
       - name: Set env vars (windows)
+        shell: bash
         if: startsWith(matrix.os, 'windows')
         run: echo "VCPKG_TRIPLET=x64-windows-static" >> $GITHUB_ENV
       - name: Set env vars(all)
+        shell: bash
         run: echo "VCPKG_RESPONSE_FILE=external/vcpkg_${{ env.VCPKG_TRIPLET }}_response_file.txt" >> $GITHUB_ENV
 
       - name: Add msbuild to PATH (windows)