Fix another species of Tesseract version number breaking regex

Fixes #795

src/ocrmypdf/_exec/tesseract.py

@@ -56,11 +56,12 @@ class TesseractLoggerAdapter(logging.LoggerAdapter):
 
 
 class TesseractVersion(StrictVersion):
+
     version_re = re.compile(
         r'''
         ^(\d+) \. (\d+) (\. (\d+))?  # groups: 1/major, 2/minor, 3/[skip], 4/patch
         [-]?  # optional hyphen separator
-        (?:(alpha|beta|rc|dev)[.\-\ ]?(\d+)?)?  # 5/prerelease, 6/prerelease_num
+        (?:(alpha|beta|rc|dev)?[.\-\ ]?(\d+)?)?  # 5/prerelease, 6/prerelease_num
         (?:-(\d+)-g[0-9a-f]+)?  # untagged git version
         $
         ''',

tests/test_validation.py

@@ -237,6 +237,13 @@ def test_version_comparison():
         need_version='4.0.0',
         version_parser=TesseractVersion,
     )
+    vd.check_external_program(
+        program="tesseract",
+        package="tesseract",
+        version_checker=lambda: 'v4.0.0.20181030',  # Some Windows builds use this format
+        need_version='4.0.0',
+        version_parser=TesseractVersion,
+    )
     vd.check_external_program(
         program="tesseract",
         package="tesseract",