set the ubuntu version to 18.04 (#69)

this is to avoid issue resulting from this change:
actions/runner-images#1816

Signed-off-by: Yuval Lifshitz <ylifshit@redhat.com>

Author: yuvalif

.github/workflows/clang-tidy.yml

@@ -8,7 +8,7 @@ env:
 
 jobs:
   clang-tidy:
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-18.04
 
     steps:
     - uses: actions/checkout@v2
@@ -23,7 +23,7 @@ jobs:
       run: sudo apt-get install -y libgtest-dev
 
     - name: install-gtest
-      run: cd /usr/src/gtest && sudo cmake . && sudo make && sudo cp lib/*.a /usr/lib
+      run: cd /usr/src/gtest && sudo cmake . && sudo make && sudo cp lib/*.a /usr/lib || sudo cp *.a /usr/lib
 
     - name: Create Build Environment
       # Some projects don't allow in-source building, so create a separate build directory

.github/workflows/cmake.yml

@@ -12,7 +12,7 @@ jobs:
     # well on Windows or Mac.  You can convert this to a matrix build if you need
     # cross-platform coverage.
     # See: https://docs.github.com/en/free-pro-team@latest/actions/learn-github-actions/managing-complex-workflows#using-a-build-matrix
-    runs-on: ubuntu-latest
+    runs-on: ubuntu-18.04
 
     steps:
     - uses: actions/checkout@v2
@@ -24,7 +24,7 @@ jobs:
       run: sudo apt-get install -y libgtest-dev
 
     - name: install-gtest
-      run: cd /usr/src/gtest && sudo cmake . && sudo make && sudo cp lib/*.a /usr/lib
+      run: cd /usr/src/gtest && sudo cmake . && sudo make && sudo cp lib/*.a /usr/lib || sudo cp *.a /usr/lib
 
     - name: Create Build Environment
       # Some projects don't allow in-source building, so create a separate build directory