Get tidy.conf more automatically

Simplify script and make it extract the version automatically.
Also clarify docs.

README.md

@@ -171,9 +171,11 @@ any other changes before tagging and releasing a new binary.
 
 If ebookmaker crashes and the traceback refers to imported packages, it
 may be that one of the packages has been updated, requiring an updated
-version of pyinstaller:
+version of pyinstaller. Try upgrading to the latest version of PyInstaller
+by finding the [latest released version](https://github.com/pyinstaller/pyinstaller/releases)
+and upgrading to it with:
 ```
-pipenv install "pyinstaller==4.7"
+pipenv install "pyinstaller==$LATEST_RELEASE"
 ```
 
 An error such as `local variable 'xxxx' referenced before assignment` may

get_tidy_conf.sh

@@ -5,10 +5,6 @@
 
 set -e
 
-VERSION=0.11.26
+VERSION=$(grep ebookmaker Pipfile | tr -d '"' | sed 's/.*==//')
 
-rm -rf ebookmaker.zip ebmtemp
-curl -L -o ebookmaker.zip https://github.com/gutenbergtools/ebookmaker/archive/refs/tags/$VERSION.zip
-unzip -q ebookmaker.zip -d ebmtemp
-cp ebmtemp/ebookmaker-$VERSION/ebookmaker/parsers/tidy.conf dist
-rm -rf ebookmaker.zip ebmtemp
+curl -L -o dist/tidy.conf https://github.com/gutenbergtools/ebookmaker/raw/$VERSION/ebookmaker/parsers/tidy.conf