Update tested Node versions list

* Get rid of old and unmaintained v10
* Add v18 and v20
* Switch integration tests to v18

.github/workflows/integration.yaml

@@ -66,10 +66,10 @@ jobs:
         with:
           toolchain: stable
           profile: minimal
-      - name: Install Node.js 10.x
+      - name: Install Node.js 18.x
         uses: actions/setup-node@v1
         with:
-          node-version: 10.x
+          node-version: 18.x
       - name: Install Emscripten
         run: |
           version=$(cat src/wrappers/themis/wasm/emscripten/VERSION)

.github/workflows/test-wasm.yaml

@@ -78,7 +78,6 @@ jobs:
     strategy:
       matrix:
         node-version:
-          - 10.x  # legacy
           - 12.x  # legacy
           - 14.x  # legacy
           - 16.x  # legacy
@@ -112,9 +111,11 @@ jobs:
     strategy:
       matrix:
         node-version:
-          - 12.x  # old LTS
-          - 14.x  # current LTS
-          - 16.x  # current stable
+          - 12.x  # legacy
+          - 14.x  # legacy
+          - 16.x  # legacy
+          - 18.x  # current LTS
+          - 20.x  # current active
       fail-fast: false
     env:
       # WasmThemis uses promises to handle asynchronous WebAssmebly compilation.