Upgrade bootstrap to version 3.4.1 (#155)

* Update version to 0.9.0

* Upgrade bootstrap to version 3.4.1. In Bootstrap 4 before 4.3.1 and Bootstrap 3 before 3.4.1, XSS is possible in the tooltip or popover data-template attribute. For more information, see: https://blog.getbootstrap.com/2019/02/13/bootstrap-4-3-1-and-3-4-1/

build/version.props

 <Project>
 	<PropertyGroup>
 		<VersionMajor>0</VersionMajor>
-		<VersionMinor>8</VersionMinor>
+		<VersionMinor>9</VersionMinor>
 		<VersionPatch>0</VersionPatch>
 		<VersionQuality></VersionQuality>
 		<VersionPrefix>$(VersionMajor).$(VersionMinor).$(VersionPatch)</VersionPrefix>

sample/SkyApm.Sample.AspNet/packages.config

 <?xml version="1.0" encoding="utf-8"?>
 <packages>
-  <package id="bootstrap" version="3.3.7" targetFramework="net45" />
+  <package id="bootstrap" version="3.4.1" targetFramework="net45" />
   <package id="Grpc" version="1.12.0" targetFramework="net45" />
   <package id="Grpc.Core" version="1.12.0" targetFramework="net45" />
   <package id="jQuery" version="1.9.1" targetFramework="net45" />