added gcc 10 to build matrix
diff --git a/.github/workflows/main.yml b/.github/workflows/main.yml
index 262cb74..9db3eff 100644
--- a/.github/workflows/main.yml
+++ b/.github/workflows/main.yml
@@ -27,6 +27,7 @@
           ubuntu-18.04-gcc-7,
           ubuntu-18.04-gcc-8,
           ubuntu-18.04-gcc-9,
+          ubuntu-18.04-gcc-10,
           ubuntu-18.04-clang-3.5,
           ubuntu-18.04-clang-3.6,
           ubuntu-18.04-clang-3.7,
diff --git a/.travis.yml b/.travis.yml
index a56b00b..a8a4797 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -127,6 +127,15 @@
           packages: ["g++-9",   "valgrind", "libc6-dbg", "linux-libc-dev"]
           sources: *apt_sources
 
+    # GCC 10
+    - env: COMPILER=g++-10 HAS_ASAN=true HAS_UBSAN=true HAS_TSAN=true SANITIZER_CXX_FLAGS="-fuse-ld=gold -static-libasan" TSAN_CXX_FLAGS="-ltsan"
+      compiler: gcc
+      sudo: required      # see this issue for more details: https://github.com/travis-ci/travis-ci/issues/9033
+      addons: &gcc10
+        apt:
+          packages: ["g++-10",   "valgrind", "libc6-dbg", "linux-libc-dev"]
+          sources: *apt_sources
+
     # Clang 3.5
     - env: COMPILER=clang++-3.5 HAS_ASAN=true HAS_UBSAN=true # no HAS_TSAN - see errors: https://travis-ci.org/onqtam/doctest/builds/417926743
       addons: &clang35
diff --git a/doc/markdown/features.md b/doc/markdown/features.md
index 1ae89ef..ff8c45e 100644
--- a/doc/markdown/features.md
+++ b/doc/markdown/features.md
@@ -22,7 +22,7 @@
 ## Extremely portable:
 
 - Standards compliant **C++11** code - should work with any **C++11** capable compiler (use tag [**1.2.9**](https://github.com/onqtam/doctest/tree/1.2.9) for C++98 and older compilers)
-- tested with **GCC**: **4.8**, **4.9**, **5**, **6**, **7**, **8**, **9**
+- tested with **GCC**: **4.8**, **4.9**, **5**, **6**, **7**, **8**, **9**, **10**
 - tested with **Clang**: **3.5**, **3.6**, **3.7**, **3.8**, **3.9**, **4**, **5**, **6**, **7**, **8**, **9** (XCode 6+)
 - tested with **MSVC**: **2015**, **2017**, **2019** (also in 32 bit mode)
 - per-commit tested on [**travis**](https://travis-ci.org/onqtam/doctest) and [**appveyor**](https://ci.appveyor.com/project/onqtam/doctest) CI services