CI: Remove caching

Slows down the build up 30 sec on both travis and appveyor, caching is pointless, dotnet restore is faster than re-using old cache.

.travis.yml

@@ -25,19 +25,10 @@ env:
     - DOTNET_SKIP_FIRST_TIME_EXPERIENCE: 1
     - RUNTIMES="generic win-x64 linux-x64 linux-arm osx-x64" # https://github.com/travis-ci/travis-ci/issues/1444
 
-cache:
-  directories:
-  - $HOME/.local/share/NuGet
-  - $HOME/.nuget
-
 before_script:
   - |
     set -e
 
-    if git diff --name-only HEAD^ HEAD | grep -Fq '.csproj'; then
-        dotnet nuget locals -c all
-    fi
-
     dotnet restore
 
 script:

appveyor.yml

@@ -10,7 +10,6 @@ configuration: Release
 platform: Any CPU
 clone_depth: 10
 environment:
-  APPVEYOR_CACHE_ENTRY_ZIP_ARGS: -t7z -mx=9
   DOTNET_CHANNEL: 2.0
   DOTNET_CLI_TELEMETRY_OPTOUT: true
   DOTNET_SKIP_FIRST_TIME_EXPERIENCE: true
@@ -31,9 +30,6 @@ install:
     Invoke-WebRequest -Uri 'https://raw.githubusercontent.com/dotnet/cli/master/scripts/obtain/dotnet-install.ps1' -OutFile '.\scripts\obtain\dotnet-install.ps1'
 
     .\scripts\obtain\dotnet-install.ps1 -Channel "$env:DOTNET_CHANNEL" -InstallDir "$env:DOTNET_INSTALL_DIR"
-cache:
-- '%LocalAppData%\NuGet -> **\*.csproj'
-- '%UserProfile%\.nuget -> **\*.csproj'
 before_build:
 - ps: >-
     $ErrorActionPreference = 'Stop'