You should rebuild your Maven project after adding new dependencies, either directly on Eclipse if you have the m2e built-in support (which you should, as explained and recommended in this question),
By right-clicking on the project name and then doing Maven->Update project (as @BackSlash suggests)
Also, looking at your pom.xml you are not nesting that <dependency> inside the <dependencies> tag, my db connector (postgress) looks something like this:
<dependencies>
<dependency>
<groupId>org.postgresql</groupId>
<artifactId>postgresql</artifactId>
<version>42.0.0.jre7</version>
</dependency>
... more <dependency> here...
</dependencies>
You can check this great link that explains how to write pom.xml files when creating and building Java projects with Maven.
Edit:
Remember to call the driver exactly like "com.mysql.jdbc.Driver", with capital 'd'.
pom.xmlfor changes to take effect