Bump lxml from 4.5.2 to 4.6.2 in /Amazon Price Alert

Bumps [lxml](https://github.com/lxml/lxml) from 4.5.2 to 4.6.2.
- [Release notes](https://github.com/lxml/lxml/releases)
- [Changelog](https://github.com/lxml/lxml/blob/master/CHANGES.txt)
- [Commits](lxml/lxml@lxml-4.5.2...lxml-4.6.2)

Signed-off-by: dependabot[bot] <[email protected]>

Author: dependabot[bot]

Amazon Price Alert/requirements.txt

@@ -6,7 +6,7 @@ chardet==3.0.4
 cssselect==1.1.0
 fake-useragent==0.1.11
 idna==2.10
-lxml==4.5.2
+lxml==4.6.2
 parse==1.18.0
 pyee==7.0.4
 pyppeteer==0.2.2