ci: remove the diffpy.srfit 3.4.0rc0 bridge and require srfit>=3.4.0

srfit 3.4.0 is on conda-forge, so CI no longer needs to pip install the
rc (reverts 000e71b). cmipdf calls methods that srfit 3.3.1 lacks (19 of
49 tests fail with it), so declare the lower bound in conda.txt and
pip.txt.

Closes #6.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: cadenmyers13

.github/workflows/matrix-and-codecov-on-merge-to-main.yml

@@ -17,8 +17,5 @@ jobs:
       project: diffpy.cmipdf
       c_extension: false
       headless: false
-      run: |
-        set -Eeuo pipefail
-        python -m pip install --no-deps diffpy.srfit==3.4.0rc0
     secrets:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}

.github/workflows/tests-on-pr.yml

@@ -11,8 +11,5 @@ jobs:
       project: diffpy.cmipdf
       c_extension: false
       headless: false
-      run: |
-        set -Eeuo pipefail
-        python -m pip install --no-deps diffpy.srfit==3.4.0rc0
     secrets:
       CODECOV_TOKEN: ${{ secrets.CODECOV_TOKEN }}

news/rm-srfit-rc-pin.rst

@@ -0,0 +1,23 @@
+**Added:**
+
+* <news item>
+
+**Changed:**
+
+* <news item>
+
+**Deprecated:**
+
+* <news item>
+
+**Removed:**
+
+* <news item>
+
+**Fixed:**
+
+* Require ``diffpy.srfit`` 3.4.0 or later. Older versions lack the methods diffpy.cmipdf calls, so installing it next to ``diffpy.srfit`` 3.3.1 failed at run time.
+
+**Security:**
+
+* <news item>

requirements/conda.txt

@@ -1,4 +1,4 @@
 numpy
 diffpy.srreal
-diffpy.srfit
+diffpy.srfit>=3.4.0
 diffpy.structure

requirements/pip.txt

@@ -1,4 +1,4 @@
 numpy
 diffpy.srreal
-diffpy.srfit
+diffpy.srfit>=3.4.0
 diffpy.structure