update and fix changelog

CHANGELOG.md

-# Pending release
+# CHANGELOG
+All notable changes to this project will be documented in this file.
 
-## New Features
+The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
+and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### New Features
 * Added back `promptE3Env.bash`, which runs `setE3Env.bash` and then sets the bash prompt.
 * Added descriptions for more targets when running `make help`
 * Added a new test target for individual modules, available as `make test`
 * Added script in `tools/test_installed_modules.sh` that tests all modules in an installation
 * Build numbers are now prefixed with a `+`.
 
-## Bugfixes
-
+### Bugfixes
 * Removed `loadIocsh` function, which was just a cover for `runScript`.
 * Removed references to `INSTBASE`
 * Fixed issue where `make cellinstall` would recompile a module.
@@ -22,11 +26,11 @@
 * Issue involving priority between some test versions fixed
 * `make patch` when there are no patch files will no longer return an error code.
 
-## Other changes
+### Other changes
 * Removed `require` as a submodule and merged it into `e3-require`.
+* Removed `plotdep` target.
 
-# 3.3.0
-
+## [3.3.0]
 3.3.0 is a relatively major release with many bugfixes and a number of features added based on consultation
 with developers. One major change is that versions are now parsed as MAJOR.MINOR.PATCH-BUILD (with build
 number being optional, assumed to be zero if not present). This has proven to be necessary in the NFS
@@ -38,8 +42,7 @@ setting for a number of separate reasons to handle dependencies properly. Note t
 
 A second major change (mostly via bugfixes) is that the local install command, `make cellinstall` which installs the module in a local directory now works properly, which allows developers and integrators to simply mount the NFS E3 build and work with that instead of needing to install E3 locally.
 
-## New Features
-
+### New Features
 * Removed all EPICS 3.* and VxWorks code, as these are not to be supported at ESS.
 * Consistent with the philosophy of not requiring module version pinning, if one specifies a dependent
   module with e.g. `REQUIRED += asyn` then the latest version of asyn will be used. No version need
@@ -57,8 +60,7 @@ A second major change (mostly via bugfixes) is that the local install command, `
 * Added a `prebuild` target that runs before build so module developers can run specific code before the build process.
 * A module developer can now install dbd files separate from the module dbd file by using `DBD_INSTALLS += file.dbd`.
   
-## Bugfixes
-
+### Bugfixes
 * Ensures that lowercase module names are enforced consistently
 * Vendor libraries are only installed at install time, not at build time
 * Vendor libraries are uninstalled when `make uninstall` is run
@@ -72,8 +74,7 @@ A second major change (mostly via bugfixes) is that the local install command, `
 * Assorted minor typos in scripts
 * Re-added functionality to have `iocsh.bash` automagically source `setE3Env.bash`.
 
-# 3.2.0
-
+## [3.2.0]
 Require 3.2.0 is the first version of require used during our initial return to the NFS implementation
 of E3. It maintains some of the work done there (modules are lowercased for consistency), but mostly
 reverts back to a similar version to require 3.1.2. One major difference is that module pinning is not
@@ -81,14 +82,18 @@ reverts back to a similar version to require 3.1.2. One major difference is that
 form `require module` instead of `require module,version` as was the case in 3.1.2. An IOC developer can
 of course pin a specific module version. If they do not, then the highest numeric version will be chosen.
 
-## New Features
-
+### New Features
 * Added -dg, -dv options to run gdb and valgrind using `iocsh.bash`
 * If `IOCNAME` is defined, then it is used in the PV names set by require instead of `REQMOD:$(hostname)-$(pid)`.
 * Reverted changes from conda require to return to NFS
 * Moved tools files from e3-require to require submodule
 
-## Bugfixes
+### Bugfixes
 
 * Fixed issue where a second user running `iocsh.bash` on a machine would be unable to create the temporary
   startup script
+
+
+[Unreleased]: https://gitlab.esss.lu.se/e3/e3-require/compare/3.3.0...HEAD
+[3.3.0]: https://gitlab.esss.lu.se/e3/e3-require/compare/3.2.0...3.3.0
+[3.2.0]: https://gitlab.esss.lu.se/e3/e3-require/-/tree/3.2.0