Better regex for finding version pragmas and replace it with >=0.0

There is a bug which stops ^0 from working.

test/cmdlineTests.sh

@@ -178,7 +178,7 @@ do
         echo " - $dir"
         cd "$dir"
         # Replace version pragmas
-        find . -name '*.sol' -type f -print0 | xargs -0 sed -i -e 's/pragma solidity [^;]+/pragma solidity ^0/'
+        find . -name '*.sol' -type f -print0 | xargs -0 sed -i -e 's/pragma solidity [\^0-9\.]*/pragma solidity >=0.0/'
         compileFull -w *.sol */*.sol
         cd ..
     fi