build: update macos deployment target to 10.13 for 14.x

Update the macos deployment target to 10.13 (High Sierra) for Node 14

refs: nodejs/build#2168

BUILDING.md

@@ -168,7 +168,7 @@ Binaries at <https://nodejs.org/download/release/> are produced on:
 | Binary package        | Platform and Toolchain                                                   |
 | --------------------- | ------------------------------------------------------------------------ |
 | aix-ppc64             | AIX 7.1 TL05 on PPC64BE with GCC 6                                       |
-| darwin-x64 (and .pkg) | macOS 10.15, Xcode Command Line Tools 11 with -mmacosx-version-min=10.10 |
+| darwin-x64 (and .pkg) | macOS 10.15, Xcode Command Line Tools 11 with -mmacosx-version-min=10.13 |
 | linux-arm64           | CentOS 7 with devtoolset-6 / GCC 6                                       |
 | linux-armv7l          | Cross-compiled on Ubuntu 16.04 x64 with [custom GCC toolchain](https://github.com/rvagg/rpi-newer-crosstools)   |
 | linux-ppc64le         | CentOS 7 with devtoolset-6 / GCC 6 <sup>[7](#fn7)</sup>                  |

common.gypi

@@ -430,7 +430,7 @@
           'GCC_ENABLE_CPP_RTTI': 'NO',              # -fno-rtti
           'GCC_ENABLE_PASCAL_STRINGS': 'NO',        # No -mpascal-strings
           'PREBINDING': 'NO',                       # No -Wl,-prebind
-          'MACOSX_DEPLOYMENT_TARGET': '10.10',      # -mmacosx-version-min=10.10
+          'MACOSX_DEPLOYMENT_TARGET': '10.13',      # -mmacosx-version-min=10.13
           'USE_HEADERMAP': 'NO',
           'OTHER_CFLAGS': [
             '-fno-strict-aliasing',