Update to version 3

- changes:
    - New structure:
      There are no .cpp files anymore, everything is implemented in header directly

- improvements:
    - No linker flags must be included anymore as everything is now implemented in header
    - Installation process is simplified: Just call "make" or "make install" (with root privileges) in root folder to install (copy) library files

.github/workflows/release.yml

@@ -12,7 +12,7 @@ jobs:
     steps:
 
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
 
       - name: Get tag name
         id: tag-name

.github/workflows/test.yml

@@ -20,7 +20,7 @@ jobs:
           sudo apt-get install -y build-essential cmake libssl-dev openssl
 
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@v4
         with:
           submodules: recursive
 
@@ -46,7 +46,7 @@ jobs:
 
       - name: Upload test results
         if: always()
-        uses: actions/upload-artifact@v3
+        uses: actions/upload-artifact@v4
         with:
           name: test-results-gtest_${{ matrix.protocol }}-${{ matrix.mode }}-${{ matrix.certType }}
           path: test/gtest/results.json