Bumped SDK version used in 'AppVeyor' and 'Travis' to 1.8.7.

Author: MrPointer

.travis.yml

@@ -4,7 +4,7 @@ os:
 - osx
 env:
 - ARDUINO_SDK_VERSION=1.6.13
-- ARDUINO_SDK_VERSION=1.8.6
+- ARDUINO_SDK_VERSION=1.8.7
 addons:
   apt:
     packages:

appveyor.yml

@@ -4,7 +4,7 @@ environment:
   MINGW_PATH: C:\mingw-w64\x86_64-7.2.0-posix-seh-rt_v5-rev1\mingw64\bin
   matrix:
   #  - ARDUINO_SDK_VERSION: 1.6.13
-  - ARDUINO_SDK_VERSION: 1.8.6
+  - ARDUINO_SDK_VERSION: 1.8.7
 install:
 - ps: cinst unzip
 - ps: $env:ARDUINO_SDK_FILE = "arduino-$env:ARDUINO_SDK_VERSION-windows.zip"