Increase precision to match Simplecov results

[aladh]

Sample XML:

<?xml version='1.0'?>
<!DOCTYPE coverage SYSTEM "http://cobertura.sourceforge.net/xml/coverage-04.dtd">
<!-- Generated by simplecov-cobertura version 3.0.1-dev (https://github.com/jessebs/simplecov-cobertura) -->
<coverage line-rate="0.8571" lines-covered="6" lines-valid="7" branches-covered="5" branches-valid="12" branch-rate="0.4167" complexity="0" version="0" timestamp="1753739500">
  <sources>
    <source>/Users/al/code/simplecov-cobertura</source>
  </sources>
  <packages>
    <package name="simplecov-cobertura" line-rate="0.8571" branch-rate="0.4167" complexity="0">
      <classes>
        <class name="test/simplecov-cobertura_test.rb" filename="test/simplecov-cobertura_test.rb" line-rate="0.8571" branch-rate="0.4167" complexity="0">
          <methods/>
          <lines>
            <line number="1" hits="1" branch="false"/>
            <line number="2" hits="1" branch="false"/>
            <line number="3" hits="1" branch="true" condition-coverage="100% (1/1)"/>
            <line number="5" hits="1" branch="true" condition-coverage="100% (1/1)"/>
            <line number="7" hits="1" branch="false"/>
            <line number="8" hits="0" branch="true" condition-coverage="0% (0/1)"/>
            <line number="10" hits="1" branch="true" condition-coverage="100% (1/1)"/>
          </lines>
        </class>
      </classes>
    </package>
  </packages>
</coverage>

[aladh]

Hey @jessebs! Could you take a look at this? Thanks!

[jessebs]

Great addition. Thank you!