Allow changing --since argument

* when PR, we want diff agaist base ref (master usually)

* when push to master or any other branch, there's no base ref so use
  HEAD~1 as the only sensible choice

* when developing locally, fallback to BASE_REF default from Makefile
  (master that is)

Author: mostlyobvious

.github/workflows/aggregate_root_mutate.yml

@@ -39,6 +39,7 @@ jobs:
       RUBY_VERSION: "${{ matrix.ruby_version }}"
       BUNDLE_GEMFILE: "${{ matrix.bundle_gemfile }}"
       BUNDLE_WITHOUT: database
+      BASE_REF: "${{ github.base_ref || 'HEAD~1' }}"
     strategy:
       fail-fast: false
       matrix:

.github/workflows/minitest-ruby_event_store_mutate.yml

@@ -29,6 +29,7 @@ jobs:
       RUBY_VERSION: "${{ matrix.ruby_version }}"
       BUNDLE_GEMFILE: "${{ matrix.bundle_gemfile }}"
       BUNDLE_WITHOUT: database
+      BASE_REF: "${{ github.base_ref || 'HEAD~1' }}"
     strategy:
       fail-fast: false
       matrix:

.github/workflows/rails_event_store_mutate.yml

@@ -39,6 +39,7 @@ jobs:
       RUBY_VERSION: "${{ matrix.ruby_version }}"
       BUNDLE_GEMFILE: "${{ matrix.bundle_gemfile }}"
       BUNDLE_WITHOUT: database
+      BASE_REF: "${{ github.base_ref || 'HEAD~1' }}"
     strategy:
       fail-fast: false
       matrix:

.github/workflows/ruby_event_store-active_record_mutate.yml

@@ -39,6 +39,7 @@ jobs:
       RUBY_VERSION: "${{ matrix.ruby_version }}"
       BUNDLE_GEMFILE: "${{ matrix.bundle_gemfile }}"
       BUNDLE_WITHOUT: database
+      BASE_REF: "${{ github.base_ref || 'HEAD~1' }}"
     strategy:
       fail-fast: false
       matrix:

.github/workflows/ruby_event_store-browser_mutate.yml

@@ -39,6 +39,7 @@ jobs:
       RUBY_VERSION: "${{ matrix.ruby_version }}"
       BUNDLE_GEMFILE: "${{ matrix.bundle_gemfile }}"
       BUNDLE_WITHOUT: database
+      BASE_REF: "${{ github.base_ref || 'HEAD~1' }}"
     strategy:
       fail-fast: false
       matrix:

.github/workflows/ruby_event_store-flipper_mutate.yml

@@ -29,6 +29,7 @@ jobs:
       RUBY_VERSION: "${{ matrix.ruby_version }}"
       BUNDLE_GEMFILE: "${{ matrix.bundle_gemfile }}"
       BUNDLE_WITHOUT: database
+      BASE_REF: "${{ github.base_ref || 'HEAD~1' }}"
     strategy:
       fail-fast: false
       matrix:

.github/workflows/ruby_event_store-newrelic_mutate.yml

@@ -29,6 +29,7 @@ jobs:
       RUBY_VERSION: "${{ matrix.ruby_version }}"
       BUNDLE_GEMFILE: "${{ matrix.bundle_gemfile }}"
       BUNDLE_WITHOUT: database
+      BASE_REF: "${{ github.base_ref || 'HEAD~1' }}"
     strategy:
       fail-fast: false
       matrix:

.github/workflows/ruby_event_store-outbox_mutate.yml

@@ -29,6 +29,7 @@ jobs:
       RUBY_VERSION: "${{ matrix.ruby_version }}"
       BUNDLE_GEMFILE: "${{ matrix.bundle_gemfile }}"
       BUNDLE_WITHOUT: database
+      BASE_REF: "${{ github.base_ref || 'HEAD~1' }}"
     strategy:
       fail-fast: false
       matrix:

.github/workflows/ruby_event_store-profiler_mutate.yml

@@ -29,6 +29,7 @@ jobs:
       RUBY_VERSION: "${{ matrix.ruby_version }}"
       BUNDLE_GEMFILE: "${{ matrix.bundle_gemfile }}"
       BUNDLE_WITHOUT: database
+      BASE_REF: "${{ github.base_ref || 'HEAD~1' }}"
     strategy:
       fail-fast: false
       matrix:

.github/workflows/ruby_event_store-protobuf_mutate.yml

@@ -29,6 +29,7 @@ jobs:
       RUBY_VERSION: "${{ matrix.ruby_version }}"
       BUNDLE_GEMFILE: "${{ matrix.bundle_gemfile }}"
       BUNDLE_WITHOUT: database
+      BASE_REF: "${{ github.base_ref || 'HEAD~1' }}"
     strategy:
       fail-fast: false
       matrix: